LearnBoost/stylus — pull request #1605 by Panya (2014-06-30 21:43:08+00:00)
Title: Allow idents and units coercion (consistent with strings)

Currently:
```scss
foo + 10px // error!
'foo' + 10px // 'foo10px'
```

After patch:
```scss
foo + 10px // foo10px
'foo' + 10px // 'foo10px'
```