roosh: add style and clear commands
roosh: add built-in names P=current pad, C=current canvas, D=current directory
roosh: better canvas handling
roosh: better style handling
Merge pull request #402 from ndawe/master

[MRG] make middle hist optional in get_band
Merge pull request #401 from ndawe/roosh

[MRG] roosh: better canvas/style handling