update the merge algorithum(unfinished)
update the merge algorithm (unfinished)
unfinished:
	logging structure
	conflict and merge logging
fix merge algorithm
	addNodeToD
	addSubGraphToD
add mergeLog to merge algorithm
reconstruct retrieve and commit
fix function checkModified
test for commit and retrieve passed
test for merge passed
fix bugs in mergeLog
reconstruct mergeControlWin
display structureLog info in selective merging interface
display attribute merge log
reconstruct MergeEditor.js and MergeEditor.setDiffColor (untested)
test of diffColor passed
bug fix for stateLog
successfully display tags and branches in scene verion history window
add removeVersion, testing passed
add branch to working state,
fix commiting bug, where branch won't move with committing
add outline color to DiffColor module, test passed