Null check for last_token.parent

Fixes #548
Minor clean up of tokenizer code
Regex tokenizing fix after typeof and yield

Fixes #547
Update beautify-css.js for LESS @var and &: parent reference

Fixes #489
Closes #496
LESS and SCSS not completely broken

Closes #356
Fixes #410
Fixes #414
Fix css comments breaking and loosing characters

Fixes #466
Fixes #506
Attempt to pass through input that we can't make sense of

Fixes #301
Do not remove indent for condtional blocks

Fixes #298
Fix for eatString not handling escapes correctly

Fixes #364
Bower and change log for 1.5.3
Python 1.5.3
1.5.3
Improved milestone description for 1.5.3
Merge remote-tracking branch 'origin/master' into gh-pages