Remove useless path construction.
Use absolute name by default.

	Improve performances by 18%.
Remove useless getter call.
DepFile: Cleanup.
DepFile: Remove useless dictionary.
Remove useless Path invocation.
Pickle dependency files directly as dictionaries.
Enable to specify the type in drake.nodes.
valgrind: Adapt to node.name changes.
TarballExtractor: Adapt to node.name changes.