Fix mutation expectations for match current line

Mutant produces an AST that is asymetric to how parser parses.
It still unparses to valid ruby so not an issue currently.
Add specs for mutations attribute assignments

* References #149
Use latest unparser from rubygems
Bump version to 0.3.3
Prepare changelog for v0.3.3
Remove unneeded require
Move parser node list to a separate file

* This should fix the "high complexity" codeclimate reports.
Reduce duplication in mutant/constants.rb via class level helper
Adjust flay score
Allow failures on rbx

Travis version is old and affected by array unpacking bug.
Add missing encoding header
Handle attribute assignments to self correctly

* Closes #149
Prepare 0.3.4
Bump parser dependency to ~> 2.1.4
Adjust flay score
Update anima dependency
Prepare version 0.3.5
Allow failures on ruby-2.1.0 anima causes it to segfault
Prepare to split mutant-rspec from gem.

* Moves all rspec integration into Mutant::Rspec namespace.
* Removes the unused --rspec-level option
* Mutant::Rspec::Strategy is smelly, has no state. Will make sense with
  future commits.
Remove unneded ivar