make the config compatible with jshint

[dan zelisko]

hi,

jshint expects identifiers to be in camelCase, but this tasks use underscores (for example: jslint_happy instead of jslintHappy.
this makes jshint fail when checking the Gruntfile.js with jsbeautifier options in it.

thanks!
dan

[Vishal Kadam]

Now configuration can be specified either camelCase or with underscores. See this commit