changed all instances of drush_backend_invoke and drush_invoke to match
the new command names.

Closes: #458250

Closes: #458250

#456622 - ensure that drush_invoke operates in a clean namespace and does not mistake drupal hooks as its own. Check the issue for the conversion script.

First import of the basis of the 0.2 release of provision. This version has a much cleaner api, through the dynamic inclusion of <command>.provision.inc files , which any module can overload. Each of these files has the exact same structure, and thus it is much clearer what happens when, and much much simpler to document / extend. I also removed all the drupal dependencies i could find, in preperation for moving to a version agnostic drush, for all buy provision_drupal (which is going to be spun off into a different project). This also includes a working update command, and keeps track of the modules installed on a site after every verify / upgrade process. This information is not being tracked in hosting, yet