matplotlib Code

prepare for 0.99.2 release

fix drawlsmask so it works for cylindrical projections that have limits
outside -180,180

added 'scale' keyword to bluemarble and warpimage to downsample background
image (replaces 'resolution' keyword from previous commit).

added low resolution option for blue marble background.

lat_ts now defaults to 0 for mercator.

now can specify just lon_0 to define global cylindrical projection
centered on lon_0.

added save_background.py example.

added new embedding_map_in_wx.py example, courtesy of Mauro Cavalcanti.

Added masked array support to shiftgrid, fix cut and paste error in
previous commit. Patch provided by Jesper Larsen.

defer import of netcdf module