Add .gitignore, modify README.

Added a .gitignore, which ignores backup (tilde) files.

I modified the coding standards in the README. Read the diff for more
info.
Add (untested) skeleton file for unit tests.

I added a skeleton file for unit tests. The skeleton was based on
[this](http://php-unit-test.sourceforge.net/). **Note: the unit test
skeleton is ironically untested.**