Remove .specification from .gitignore

Re: https://github.com/binarylogic/authlogic/issues/107

This allows authlogic to be vendored with a .specification file. 

Also unclear why it was originally added to .gitignore
Fixed typo in comment

changed comprising to compromising
Merge pull request #430 from chamini2/master

Fixed typo in comment
Fixes validation for magic columns
Merge pull request #431 from tom-kuca/patch-1

Fixes validation for magic columns