[infra] First draft of the package's features
[infra] set up build and packaging
[doc] set up sphinx documentation
[pypmc] First version of MCMC proposal densities

o modelled after eos implementation and unit tests
[proposal_test.py] - test_propose function now also
                     check variance, not only mean
                   - added comments:
                     "test if value for rng can be omitted"
[proposal.py]  - made some variables private by
                 renaming them var --> _var
               - _inherit_docstring decorator
                  introduced (see also: tools.py)

[_tools.py]    - private helper functions introduced
               - _inherit_docstring decorator
                 introduced (see also: proposal.py)

[version.py]   - renamed to _version.py
[proposal.py]  - merged classes ProposalDensity and AdaptiveProposal
                 into the single class ProposalDensity

[__init__.py]  - modified the imports to be module level imports
added new modules: indicator_factory, markov_chain
moved all work to the new submodule "mcprerun"
made all relative imports explicitly relative (from . import ...)

tested with nosetests for python 2.7 and for python 3

Signed-off-by: Stephan Jahn <gu92biv@mytum.de>