Finish creating HHI files for PHPUnit_Framework

Everything under `PHPUnit_Framework` that's included in `phpunit/phpunit` now has HHI files.

Closes #3.

See merge request !4

Create the initial README file

Closes #2

See merge request !3

Comment out the DOMElement type hints

Temporary workaround for https://github.com/facebook/hhvm/issues/5322.
Will revert once there's a stable HHVM with DOMElement HHI.

Further work to remove all errors reported in #1.

See merge request !2

Temporary workaround for https://github.com/facebook/hhvm/issues/5322.
Will revert once there's a stable HHVM with DOMElement HHI.

Implement missing PHPUnit classes

Provides HHI files for a bunch more PHPUnit classes.

Removes types from places where the specified class is in another package (mock objects and code coverage).

Fixes #1

See merge request !1