Changed name of main command and aliases.

  drushsubtree -> drushsubtree-build
               -> alias subtree-build
               -> alias dsb

	modified:   README.md
	modified:   drushsubtree.drush.inc
Added stubs for Commander and SubtreeCommander classes.

  Begin reorganizing subtree.

	new file:   drushsubtree.commander.class.inc
	modified:   drushsubtree.drush.inc
	new file:   drushsubtree.subtreecommander.class.inc
Added buildmanager extenstion.

  Move build management functionality out of drushsubtree into its own project.

	renamed:    drushsubtree.example-dev.yml -> buildmanager.example-dev.yml
	renamed:    drushsubtree.example-prod.yml -> buildmanager.example-prod.yml

	new file:   buildmanager.drush.inc
	modified:   drushsubtree.drush.inc

	new file:   .gitignore
	new file:   TODO-buildmanager.txt
Added hook_buildmanager_build, hook_buildmanager_build_options.

	modified:   buildmanager.drush.inc
	modified:   drushsubtree.drush.inc

	modified:   README.md
	modified:   buildmanager.example-dev.yml
	modified:   buildmanager.example-prod.yml
Added basic SubtreeCommander class architecture and ::add().

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Added SubtreeCommander::pull().

  Refactored hook_buildmaster_build to use $subtree->pull().

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Added drushsubtree-pull (subtree-pull) command. Fixed pull bug.

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Added SubtreeCommander::merge() and drushsubtree-merge command.

	modified:   buildmanager.drush.inc
	modified:   drushsubtree.drush.inc
	new file:   drushsubtree.gitcommander.class.inc
	modified:   drushsubtree.subtreecommander.class.inc
Fixed bug in drushsubtree-merge.

  Now merging to specified ID and tag again.

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Minor update for consistency: SubtreeCommander::add().

	modified:   drushsubtree.subtreecommander.class.inc
Minor fix to drush_log call to dt().

	modified:   drushsubtree.subtreecommander.class.inc
Added SubtreeCommander::push() and drushsubtree-push command.

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Added id as param to drushsubtree-merge command.

	modified:   drushsubtree.drush.inc
Minor updates to subtree merging.

  Updated some stuff for consistency and resilience.

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc
Added faux subtree checkout command.

	modified:   drushsubtree.drush.inc
	modified:   drushsubtree.subtreecommander.class.inc