Merge pull request #170 from EricChiang/master

stat_function added
removed marker from geom_point aes, shape aes now works. addresses #154
Merge pull request #177 from funnell/geom_point_shape

removed marker from geom_point aes, shape aes now works. addresses #154
DOC: add doc requirements for readthedocs

Also add numpy to require in setup.py at the *last* position
so that installs on readthedocs.org work *before* all other
packages and move statsmodels to the first position
(-> installed last) so that stasmodels can be installed when
ggplots "python setup.py install" is run.
DOC: fix contributing documentation

code in contributing.rst doe snot need to be executed, as it
is exmaples of a new geom. So stop that :-)
todo: mark some of the items as inplemented
DOC: print plots in docstring examples

Also add stat_function to API docs.
DOC: small fix in section heading
Merge pull request #180 from JanSchulz/readthedocs

Add changes to make docs compile on readthedocs
added geom_rect. closes #171
added tests, raise exception on missing required aes as per PR comments.
updated subdir extraction in ggplot/tests/__init__.py to handle .pyc files
properly strip extension from test file basename
updated geom_rect docstring, removed redundant colour aes handling, set default face colour
updating geom_rect_plus.png to reflect default fill colour
Merge pull request #184 from funnell/geom_rect

added geom_rect. addresses #171
removed embedded formatting in README.rst hyperlinks
geom_rect: added default colour, bug fix for setting xmax, ymax outside aes(), unit test update/reorganization
changed bar's defaults to be thicker and black
Merge pull request #195 from funnell/geom_bar_visual_update

changed geom_bar's defaults to be thicker and black