HTML reporter now no longer works with browserify-istanbul in v4.0

HTML reporter now no longer works with browserify-istanbul in v4.0

I was having issues with the html reporter not outputting anything in v3.1 where the index.html would be written, but no reports would be contained inside (while the text reporter was working fine) so after seeing issue #123 I jumped to 4.0. Now I am getting the following issue:

```
ERROR [coverage]: [TypeError: Cannot read property 'text' of undefined]
TypeError: Cannot read property 'text' of undefined
at /home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:203:51
at Array.forEach (native)
at annotateStatements (/home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:188:33)
at HtmlReport.Report.mix.writeDetailPage (/home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:427:9)
at /home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:488:26
at SyncFileWriter.extend.writeFile (/home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/util/file-writer.js:57:9)
at FileWriter.extend.writeFile (/home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/util/file-writer.js:147:23)
at /home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:487:24
at Array.forEach (native)
at HtmlReport.Report.mix.writeFiles (/home/notnarb/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js:481:23)
```

I made a temporary fix which now has the html reporter working properly (as far as I can tell, but certainly better than 0.3.1) - but I'm sure this isn't the proper solution

```
# node_modules/* - old, ~/tmp/html.js - new
diff ~/Workspace/snip/node_modules/karma-coverage/node_modules/istanbul/lib/report/html.js ~/tmp/html.js
200a201
> if (structuredText[startLine]) {
209a211
> }
231a234
> if (structuredText[startLine]) {
240a244
> }
```

Sorry that I can't be of too much more help than this -- I don't really understand the inner-workings of instanbul and karma-coverage, all I can determine is that for some reason a faulty startline is being communicated occasionally causing istanbul to crash and burn.
## karma.conf.js

``` javascript
// Karma configuration
// Generated on Fri May 29 2015 17:32:24 GMT-0700 (PDT)

module.exports = function(config) {
config.set({

// base path that will be used to resolve all patterns (eg. files, exclude)
basePath: '',

// frameworks to use
// available frameworks: https://npmjs.org/browse/keyword/karma-adapter
frameworks: ['browserify', 'mocha'],

// list of files / patterns to load in the browser
files: [
'test/**/*.js',
'src/js/vendor/**/*.js'
],

// list of files to exclude
exclude: [
],

// preprocess matching files before serving them to the browser
// available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
preprocessors: {
'test/**/*.js' : ['browserify']
},

browserify: {
debug: true,
transform: ['hbsfy', 'browserify-istanbul']
},

// test results reporter to use
// possible values: 'dots', 'progress'
// available reporters: https://npmjs.org/browse/keyword/karma-reporter
reporters: ['progress', 'coverage'],

coverageReporter: {
reporters : [
{"type": "text"},
{"type": "html", dir: 'coverages'}
]
},

// web server port
port: 9876,

// enable / disable colors in the output (reporters and logs)
colors: true,

// level of logging
// possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
logLevel: config.LOG_DEBUG,

// enable / disable watching file and executing tests whenever any file changes
autoWatch: true,

// start these browsers
// available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
browsers: ['Firefox'],

// Continuous Integration mode
// if true, Karma captures browsers, runs the tests and exits
singleRun: false
});
};
```
## package.json

``` javascript
{
"browserify": "^10.2.1",
"browserify-istanbul": "^0.2.1",
"karma": "^0.12.35",
"karma-browserify": "^4.2.1",
"karma-chrome-launcher": "^0.1.12",
"karma-coverage": "^0.4.0",
"karma-firefox-launcher": "^0.1.6",
"karma-mocha": "^0.1.10",
}
```

---

One thing worth reiterating: I couldn't get html reports to work at all in 3.1 and now they work great with my hacky patch

Reproduce the failure with the provided karma.conf.js and package.json versions, then inspect istanbul/lib/report/html.js around annotateStatements and the reported lines 188-240. Compare the HTML reporter behavior with the text reporter and the temporary changes shown in the issue. Done means the HTML report is generated without the TypeError for the browserify-istanbul setup, with regression coverage for the failing case.

Written by the indexing model from the issue text.