assume that everything that is non-1.8 is 1.9-compatible code

This fixes the issue with installing on ruby 2.0
remove swap!

It was a nice trick, but honestly ...
fix tests for NoMethodError being properly thrown in dsl_exec and load_dsl_file

Recent ruby 1.9 versions raise NameError if an undefined call can
either be a method or local variable missing. Append () to make
sure that it gets interpreted as a method call.
prepend ./ in front of relative requires, as needed by ruby 1.9 and later
git: add ignores required by the move to rake-compiler and yard