renamed ggpplot to ggplot
Added step to download sampledata
Added documentation to show the various palettes that are installed.  The html generated in the palettes.rst file is created using a python function, not sure if there is automated way to run this function and populate the html automatically.  A link was also added to the _glyph_functions.py module under the image function to point to the documentation.
removed bokeh build under sphinx
Altered Makefile to build palettes
altered tag _palettes to _bokeh_dot_palettes to follow convention
Merge pull request #1333 from dvreed77/dvreed77/palette-docs

Dvreed77/palette docs