Logic Error, Combination, Fault Catching

Fixed a Success/Threat Logic Error (Thanks knowles!)
Added in runtime command for Combinations (-C)
Script quits gracefully if not given a proper string.
Added Header
Whoops.

Look, it was a silly mistake.
Fixed Fault Catching. Kek.
Created Readme.
Update README.md

Spacing Issues Rectified.
Merge branch 'master' of https://github.com/Neolitheon/EotE-Dice-Probability