Merge pull request #374 from sjsrey/viz

shrinking colorbar
Adding Baltimore example dataset for use with LM models.
Merge pull request #376 from pedrovma/baltim_data

Adding Baltimore example dataset for use with LM models.
Merge pull request #375 from sjsrey/viz

greys for classless map
Fixing ignorance of argument cmap in base_choropleth_unique
Changing cmap default in plot_choropleth so every type defaults to its own adecuate colormap
Merge pull request #377 from darribas/master

Customized default cmap for `plot_choropleth`
Update README.md
BUG: fix for the comment
https://github.com/pysal/pysal/issues/244#issuecomment-30055558
Merge pull request #379 from sjsrey/b244

BUG: fix for part of b244