Remove Devtools

* Remove devtools
* Add Rake
* Add Rubinius specific dependencies
* Add RSpec
  * Use RSpec 2.99 to prepare step to RSpec 3.0
  * Add according rake tasks

In the next commits, re-add the wanted functionality step by step
Code Coverage

* Use the CodeClimate Coverage Reporter
* Remove coverage analysis during the local test runner
* Remove everything from Coveralls
Remove Flay and Flog. They run on Code Climate.
Re-add YARD and the according Rake task
Remove Yardstick, configure Inch

Inch works now. It also has a Raketask to report it.
Re-add Reek and the according Rake task
Re-add Rubocop and the according Rake task
Re-add mutant and the according Rake task
Start a console with Ashikawa::Core loaded via rake console

http://erniemiller.org/2014/02/05/7-lines-every-gems-rakefile-should-have

But using Pry instead of IRB
Organized Rakefile
Update Dependency: inch

This means we don't need this extra `require` any longer
Add Reek to the CI task
Guard is working again: Run bundler and rspec
Merge pull request #93 from triAGENS/remove-devtools

Remove Devtools [WIP]