Added examples and backends to setup.py to address #531
Remove `pymc.backends` from package list

This relates to an unmerged PR and was unintentionally added in previous
commit.
Fixed examples install issue #531
Added __init__.py to examples/data
Install test data alongside examples; fixes https://github.com/pymc-devs/pymc/issues/531
Merge pull request #533 from andrewclegg/examples_install

Install test data alongside examples; fixes https://github.com/pymc-devs...
Fixed quantiles=False bug in forestplot to address #551
Add example about using custom density distributions.

The new example is inspired by Jake Vanderplas' blog post
http://jakevdp.github.io/blog/2014/06/14/frequentism-and-bayesianism-4-bayesian-in-python/
Add links to Getting Started section.
Allowed Poisson mean to equal zero
Merge branch 'master' of github.com:pymc-devs/pymc
Update continuous.py

Correct the definition of the mode for the gamma function
Merge pull request #570 from aloctavodia/patch-1

Fix median of Gamma distribution (should instead be the mode).
Fix indexing bug into float.
Merge branch 'master' into examples_install

Conflicts:
	setup.py
Merge branch 'examples_install'
Removed point.py and references to it
Removed .RData
Add backends back to package list

This was unintentionally removed during with a merge conflict (65cd423).
Made all import statements use relative paths