Create seil.cfg

PCKeyboardHack was renamed Seil. The new version saves preferences to a renamed file.
Added Seil to README.md
Added Seil change
Delete pckeyboardhack.cfg

It's configs have been moved to Seil, which is the new name of the software.
Update seil.cfg

Pulled PCKeyboardBack's configs into this file.
Update README.md

Removed PCKeyboardHack, since it's now named of Seil.
Update CHANGELOG.md
Merge pull request #290 from kfinlay/patch-5

Create seil.cfg