Fix the RegExp constructor.

When called as a function, the RegExp constructor did not
work properly. This commit makes it instantiate itself
when called as a function.
Merge pull request #114 from SBSTP/regexp-constructor-2

Fix the RegExp constructor.
Handling char class like \s within char class.

Issue: https://github.com/maximecb/Higgs/issues/110
Merge pull request #115 from zimbabao/handling-charclass-in-charclass

Handling char class like \s within char class.
- Created quick version of string-tagcloud benchmark
Merge branch 'master' of github.com:maximecb/Higgs into dls2014
- Added string-tagcloud to `make test`