Merge pull request #95 from Rademade/master

Extract performer class for rake tasks
cleanup after #95 [ci skip]
Added devDependencies capabilities and README
checking RAILS_ENV to resolve install task
Extract root_path in a method for Performer class

Reason: https://github.com/42dev/bower-rails/commit/3333a6031be4f0ee5c87c70fe5499b172e816e30#commitcomment-7076840
Fix merge conflicts #93
Merge branch 'ValMilkevich-master'
Merge branch 'upstream/master'
Remove root_path dependencies from dsl