make Canvas and Pad context managers
Merge pull request #452 from ndawe/master

[MRG] make Canvas and Pad context managers
improved Hist.quantiles method and support both numpy for speed and pure python as fallback
Merge pull request #453 from ndawe/master

[MRG] improved Hist.quantiles method
hist: new rebinned method for all binning cases (by group or by explicit list of edges) and for all dimensions
Merge pull request #454 from ndawe/master

[MRG] hist: new rebinned method for all rebinning cases and for all dimensions
hist: fix rebinned for ROOT 5.32
Merge pull request #457 from ndawe/master

hist: fix rebinned for ROOT 5.32
fix regression reported in #451: instance-check of _Graph1DBase instead of Graph
root2matplotlib: unit tests
Merge pull request #456 from ndawe/master

[MRG] fix regressions in root2matplotlib and add unit tests
disable tests if libRooFit and libRooStats are not available
root2matplotlib: fix backend in unit tests
Merge pull request #458 from ndawe/master

[MRG] unit test fixes
hist: quantiles of 2D and 3D histograms by first projecting onto the selected axis
Merge pull request #455 from ndawe/quantiles

[MRG] hist: quantiles also works on 2D and 3D histograms
root2matplotlib: docs
Merge pull request #459 from ndawe/master

[MRG] root2matplotlib: docs
update sphinx makefile
minor example fix