Globbing & building dynamic files object.

***Non backwards compatible.***

Needed globbing to add specific files with a matching filename segment.
Previously we could only add directory's and remove matched files.

- Dynamic files object supported
- Globbing supported in replacement of `exclude`.
- No functions are leaked globally, style similar to
[copy](https://github.com/gruntjs/grunt-contrib-copy).
- Updated Readme & tests.

- `exclude`: In favor of globbing.
- `recurse`: In favor of globbing.
- `cwd`: Now using grunts native `cwd` option.
- `type`: In favor of globbing.