Fix the lower case first letter for first word

The PR fixes the handling of 'lowFirstLetter' to make it consistent with http://api.rubyonrails.org/classes/String.html#method-i-camelize. 

For example,

camelize('FooBar', true); ==> 'FooBar' (before fix)
camelize('FooBar', true); ==> 'fooBar' (after fix)