Removed options and use standard file handling from grunt-contrib projects.

The current version of the react plugin is difficult/impossible to configure.
- If you have a combination of JSX and JS files, you are only allowed one extension.
- You have to manually set all paths to all your view locations, there is no dynamic option.
- Combing cannot be done with standard file options.
- Using *files* is misleading when you actually mean *directories*.

These updates essentially remove the options and use standard file handling that can be found in many of the grunt-contrib projects. This allows standard path and extension handling with globs, combining and all the dynamic options. This makes it far more flexible in terms of how to find your files and where they are compiled to. It also keeps the handling the same as other plugins making it easier to standardize.

**NB**: These are breaking changes to existing task configs since files patterns are now used instead of directory paths. The best option to reproduce the same functionality is to change the task config to the dynamic version. This is reflected in the reader updates.