UI: Simplify job progress bar

Closes issue #65
UI: Hold project view during branch creation

The async branching process temporarily points new branches
to the original graph, which can cause issues if modifying
the graph before the new branch points to the correct graph.
This temporary fix simply polls the branches periodically and
blocks that project's view until the graph has switched.

TODO: modify backend to either:
- store parent-child branch lineage (i.e. branch.parentBranchId)
- store back-pointers from graphs to branches (i.e. graph.branchId)
Merge pull request #98 from kylef-lab41/pr-jscleanup

Handle async branch creation and cleanup style of progress bars