Implementing -h/--help flag

with usage string copied from 1.9.3-p194, then commenting out
yet-to-be-implemented flags.
Changes per feedback

including implementation of "--" flag to stop consuming args.
Improving tests per feedback
Implement Array#replace
Tweak Array#replace:

- Use other_w as parameter name
- Use same code for replace and initialize_copy
Implement String.capitalize/capitalize!
Single style guide fix
Merge pull request #353 from judofyr/array-replace

Implement Array#replace
Merge pull request #355 from winks/master

Implement String.capitalize/capitalize!
Merge pull request #356 from michelboaventura/master

Allow Module#module_function to receive any number of arguments
remove noop in tests
Merge pull request #351 from modcloth/help-flag

Implementing -h/--help flag
format more like other tests
small cleanup