Failed to load the css-edit-groups package

Nobody has claimed this yet.

This happened immediately after installing it.

**Atom**: 1.18.0 x64
**Electron**: 1.3.15
**OS**: Mac OS X 10.12.5
**Thrown From**: [css-edit-groups](https://github.com/ekonstantinidis/css-edit-groups) package 0.4.2

### Stack Trace

Failed to load the css-edit-groups package

```
At Duplicate key 'cmd-l'

Error: Duplicate key 'cmd-l'
at Object.detectDuplicateKeys (/Applications/Atom.app/Contents/Resources/app/node_modules/season/lib/cson.js:272:19)
at /Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:117:44
at Array.reduce (native)
at Obj (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:109:36)
at transformNode (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:199:18)
at Value (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:81:20)
at transformNode (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:199:18)
at /Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:116:23
at Array.reduce (native)
at Obj (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:109:36)
at transformNode (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:199:18)
at Value (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:81:20)
at transformNode (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:199:18)
at Block (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:78:20)
at transformNode (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:199:18)
at Object.parse (/Applications/Atom.app/Contents/Resources/app/node_modules/cson-parser/lib/parse.js:205:18)
at parseObject (/Applications/Atom.app/Contents/Resources/app/node_modules/season/lib/cson.js:46:29)
at parseContentsSync (/Applications/Atom.app/Contents/Resources/app/node_modules/season/lib/cson.js:72:22)
at Object.readFileSync (/Applications/Atom.app/Contents/Resources/app/node_modules/season/lib/cson.js:174:20)
at /Applications/Atom.app/Contents/Resources/app/src/package.js:489:44
at Array.map (native)
at Package.module.exports.Package.loadKeymaps (/Applications/Atom.app/Contents/Resources/app/src/package.js:486:52)
at /Applications/Atom.app/Contents/Resources/app/src/package.js:149:25
at Package.module.exports.Package.measure (/Applications/Atom.app/Contents/Resources/app/src/package.js:99:21)
at Package.module.exports.Package.load (/Applications/Atom.app/Contents/Resources/app/src/package.js:144:18)
at PackageManager.module.exports.PackageManager.loadAvailablePackage (/Applications/Atom.app/Contents/Resources/app/src/package-manager.js:565:22)
at PackageManager.module.exports.PackageManager.loadPackage (/Applications/Atom.app/Contents/Resources/app/src/package-manager.js:495:27)
at PackageManager.module.exports.PackageManager.activatePackage (/Applications/Atom.app/Contents/Resources/app/src/package-manager.js:643:36)
at /Applications/Atom.app/Contents/Resources/app/node_modules/settings-view/lib/package-manager.js:519:35
at exit (/Applications/Atom.app/Contents/Resources/app/node_modules/settings-view/lib/package-manager.js:128:22)
at triggerExitCallback (/Applications/Atom.app/Contents/Resources/app/src/buffered-process.js:338:17)
at /Applications/Atom.app/Contents/Resources/app/src/buffered-process.js:351:17
at Socket. (/Applications/Atom.app/Contents/Resources/app/src/buffered-process.js:220:15)
at emitOne (events.js:101:20)
at Socket.emit (events.js:188:7)
at Pipe._handle.close [as _onclose] (net.js:493:12)
```

### Commands

```
2x -0:33.8.0 core:confirm (input.hidden-input)
```

### Non-Core Packages

```
ariake-dark-syntax 0.1.3
color-picker 2.2.5
css-edit-groups 0.4.2
programmer-syntax 2.0.0
```

Start by inspecting the css-edit-groups package's keymap declarations, following Atom's loadKeymaps path and the reported duplicate `cmd-l` key. Reinstall or activate package 0.4.2 to reproduce the failure; done means the package loads without the duplicate-key error.

Written by the indexing model from the issue text.