add performance profiling feature
Maxflow return multiple obj
Merge branch 'feature/sstring' into develop
Merge branch 'develop' into HEAD
Update ProfilingBD
Merge branch 'feature/eval' into develop
fix argument error
fix include file error
Add XPregelGraph method for direct edge manipulation
modify graph class. Now it can accept discrete edgelist
add EdgeList type
add SimpleTextReader
Merge remote-tracking branch 'origin/develop' into feature/graph
modify io related codes
fix a bug on CSVReader
minor modification
Merge branch 'feature/graph' into develop
CSVWriter is added. FileNameProvider, MemoryChunk, CSVReaderTest are modified.
remove Attribute class
Merge remote-tracking branch 'origin/feature/sstring' into feature/io

Conflicts:
	src/org/scalegraph/io/impl/CSVWriter.x10
	src/org/scalegraph/io/impl/FileNameProvider.x10
	src/test/CSVReaderTest.x10