Browserify support + custom format function support + custom jQuery support

This PR includes support for three different things:

- Browserify. Besides AMD support and using browser globals, you can now also use Browserify. Just require() the module, and jQuery Timepicker will attach itself to the jquery module.

- Custom format functions. Besides the ability to specify a 'timeFormat' string, you can specify a function for formatting. This is useful if your codebase already contains time formatting methods.

- Custom jQuery builds. Using jQuery's build system it is possible to remove Sizzle from the jQuery build. This makes the build smaller and actually provides better runtime performance. jQuery Timepicker will now play nice with such builds by no longer relying on the ":visible" selector.