Added fail quietly option to SubtreeCommander::add().

 	modified:   drushsubtree.subtreecommander.class.inc
Added buildmanager-configure (bmc) intereactive command and related hooks.

  New hook: hook_buildmanager_configure()

	modified:   README.md
	modified:   buildmanager.drush.inc
Added implementation of hook_buildmanager_configure().

  Prompts user to enter info and then generates buildmanager config file.

	modified:   drushsubtree.drush.inc