Fixing isNaN edge case. Fixed according to the spec ecma 262 5.1
Merge pull request #82 from zimbabao/nan-edge-case-fix

Fixing isNaN edge case. Fixed according to the spec ecma 262 5.1
Merge branch 'master' of github.com:maximecb/Higgs into dev-maxime
- Fixed regular string literals accepting newlines
- Partial support for quasis as multi-line strings
- Added string parser tests