Relative paths in karma.conf.js and test-main.js for requirejs

It seems that in the `karma.conf.js`, the files array will not accept relative paths above the `basePath`. It also seems like the requirejs config the `baseUrl` is not accepting relative paths, altho maybe that's because I'm getting messed up with the whole `/base` thing (see issue https://github.com/karma-runner/karma/issues/1607).

I think it is best to try to handle relative paths as people are used to (with node's require and so on), so any unexpected hurdles to this should be removed if at all possible.

There's a related unanswered Stackoverflow question: [Karma and RequireJS getting files outside base url](http://stackoverflow.com/questions/29824193/karma-and-requirejs-getting-files-outside-base-url?rq=1).

If the answer is `wontfix`, that's understandable I suppose and I can close this.

Start by examining karma.conf.js and test-main.js, focusing on how basePath, the files array, and RequireJS baseUrl handle paths outside the base directory. Reproduce the reported behavior using the linked Karma issue and Stack Overflow question as context. Done means establishing whether relative paths can work as requested or documenting a clear wontfix outcome.

Written by the indexing model from the issue text.