incremental fixes for #269
fix the cloning of Plottables
fork fewer processes in file lock test
fix TreeTests: TFile.Close the temp files but keep the tempfile descriptors open
also swallow extra setters in Plottable.__init__
check for ambiguous setting of both color and linecolor etc. and add unit tests
fix handling of _post_init in Hist classes and add unit test for HistStack
Merge pull request #270 from ndawe/master

Fix #269