Refactor directory structure.

- Requiring /some/path.rb will no longer auto-require all features in
that and child paths. To require files en masse, use /some/path/all.rb.
- All files matching /some/path/require.rb have been removed, and the
module definitions moved to the respective /some/path.rb file.
- Ruby 1.9.3 is no longer supported.

Current Spec Status:
- 2.0: 215 examples, 0 failures in 0.2431 seconds.
- 2.1: 238 examples, 0 failures in 0.08355 seconds.
Add missing files.

- Remove conditional compilation for versions prior to 2.0.0.

Current spec status:
- 2.0: 215 examples, 0 failures in 0.11671 seconds.
- 2.1: 238 examples, 0 failures in 0.08181 seconds.
Merge pull request #3 from sleepingkingstudios/refactor-files

Refactor directory structure.