first PHP assignment
correct path issue
add `wordy` PHP assignment
Delete PHP unit testing library
Clean up PHP test process:

- drop `phpunit.phar`
- `make` driven test
PHP setup for Travis:

- install a sane PHP 5.x for travis since there is none by default on a Ruby VM.
- clean up PHPUnit-based tests for better portability.
Move exercises out of subdirectory
Add php exercises
Add gitignore
Add MIT license