Add precision to lib_round
Fixed Deprecation in PHP6

Accessing Strings via Curly brackets will be deprecated in PHP6
http://php.net/manual/de/language.types.string.php#example-58 (above this example)

also i don't think it is as readable as brackets
Merge pull request #400 from Handfeger/master

Using square brackets instead of curly brackets to access string content
Fix typo in docs/docs.md

constrast -> contrast
Merge pull request #406 from TimWolla/patch-1

Fix typo in docs/docs.md
Adding viewport directives
Adding to directive tests
Merge pull request #407 from AnhNhan/master

Adding `@viewport` directive and relatives
don't mixin self when calling without args, fixes #412 #405
Made the third parameter of mix() optional to match less.js

Closes #425
Merge pull request #427 from Incenteev/lessjs_mix

Made the third parameter of mix() optional to match less.js
Add a missing parenthesis
Merge pull request #446 from tzi/pr__documentation-typo

Add a missing parenthesis
parse semicolons in arg def
parse calling mixin args with argumentDef
delete some uneeded code
oops, delete logging
zipSetArgs takes keyword args
patternMatch uses keyword arguments
fix parsing for arg def when , list follows ;