Created startup-once and startup-always folders for running scripts on every vagrant up.
Added documentation about how to use startup-once and startup-always folders.
Fixed error where {exec-once} folders were run every time
Merge branch 'master' of https://github.com/ikari7789/puphpet into ikari7789-master

Conflicts:
	src/Puphpet/MainBundle/Resources/views/manifest/puphpet/shell/execute-files.sh