Cleanup code according to coffeelint
Do not use "-> return" to mark empty function
Prepare 0.124
Merge pull request #3116 from maschs/ms-srcLint

coffeelint!
Upgrade to language-html@0.25
Run benchmarks passes specDir
Correctly bootstrap the benchmarks
Fix benchmark requires
:lipstick: Tighten lint rules

coffeelint.json had some rules set to ignore, but since #3116 was merged there
are no violations of these rules in the code anymore. Tighten up the rules to
prevent those kinds of errors from creeping back in.

Test Plan:

Lint executes without finding any errors

```
$ ./script/grunt coffeelint
Running "coffeelint:src" (coffeelint) task
>> 80 files lint free.

Running "coffeelint:build" (coffeelint) task
>> 23 files lint free.

Running "coffeelint:test" (coffeelint) task
>> 40 files lint free.
Done, without errors.
```
Upgrade to language-coffee-script@0.30
:lipstick: more lint rules
:lipstick: arrow spacing warn -> error
Upgrade to styleguide@0.30
remove line_endings rule
Merge pull request #3295 from dmnd/tighten-lint-rules

Tighten lint rules
Add grammar scope to EditorView

Only works when the `grammar-changed` event has been triggered,
and only implemented for Space Pen views.
Use data attribute instead of CSS classes
Make sure the scope data attribute is always set
Implement support for React Editor
Change attribute name to `data-grammar`