Allows possibility of deleting several branches

This commit intends to allow passing several branches to be deleted
Usage: git chop [branch1] [branch2]
Covers the feature in the README

It also improves the README in the reader perspective
Address PR comment

Using the unix way of specifying multiple files
Merge pull request #18 from Davidslv/make-git-chop-accept-several-branches

Allows possibility of deleting several branches