transparent background & better labels position

Partially rewritten to handle transparent background (defining
background color is currently not optional); labels are better
positioned.
Tested only on cairoCanvas.
Merge remote-tracking branch 'gg_upstream/master' into TransparentDrawing_Oct2013
doesn't look completely terrible
that printing is not really necessary
increase the bounding box size
Merge pull request #143 from sriniker/master

update AssignBondOrderFromTemplate to work with protein-ligand complex
doc update for release
fragmentOnBonds() fix
Merge branch 'master' of https://github.com/rdkit/rdkit
add bondTypes and associated tests for FragmentOnBonds()
prep for next release
Merge remote-tracking branch 'origin'
aded swig output dir
Fixes #144
further refinements to the drawing
minor improvements to the aggdraw canvas
fix a clang compiler warning
remove another clang warning
this also fixes a bug with topological torsions and client-provided invariants
Fixes #146
more tuning