Enabling persistent cache to cache file using pipe mechanisim
recipes and steps now are saved into the cache
Caching recipe with the persistent cache mechanism and cleaning code
Removed trailing whitespace (arg!)
updating persistent cache
Merge branch 'persistent_cache'

Conflicts:
	lib/kameleon.rb
	lib/kameleon/cli.rb
	lib/kameleon/context.rb
	lib/kameleon/engine.rb
	lib/kameleon/persistent_cache.rb
Merging persistent cache
Adding missing methods
Now recipe is stored in cache
Merge branch 'persistent_cache' of https://github.com/oar-team/kameleon into persistent_cache

Conflicts:
	lib/kameleon.rb
	lib/kameleon/cli.rb
	lib/kameleon/context.rb
	lib/kameleon/engine.rb
	lib/kameleon/persistent_cache.rb
Adding proxy_cache varible for context
Adding doc for persistent cache variables
Merge branch 'persistent_cache' into dev