Incremental builds

[gakimball]

If an instance of Supercollider is run multiple times on the same files (which will always happen in a task runner that re-runs tasks when files change), the initial component tree generated is added to instead of replaced.

Every component (file) is one object in the Supercollider.tree array. When a file comes through, a check should be done to see if a component/file with the same name already exists in the tree. If it does, the old object should be replaced with the new one. This will prevent duplicate entires from appearing.

[gakimball]

Implemented via cd2bb18