fix ref model (tag shows)
move Hash -> common module
commit -> log_data
fix graph test
fast Node.getDownEdges()
Commit -> CommitParents
CommitParents -> interface
+SimpleCommitParents
+TimestampCommitParents
add new module git_reader
add CommitReaders
add commitHash to CommitData
controller.CommitDataReader & RefReader -> git_reader module
graph_model exported graph
add new module: data_model & new CommitDataGetter
add DataLoaderImpl with template for DataPackImpl
add DataPackImpl
add CommitDataGetter.getCommitData(Hash)
add method getCommitNodeInRow to Graph interface
DataPack.getRefModel -> getRefsModel
rebase ui_controller
remove print parameters from ui_controller