Fix name of dir
moved headers folder ruby-2.1.0 to ruby-2.1.0-p0 to match what the code expects.
Bump to version 1.3.1
give cred
Merge branch 'master' of git://github.com/cldwalker/debugger-ruby_core_source

Conflicts:
	lib/debugger/ruby_core_source/version.rb
Version