Added initial documentation

Added initial documentation for the core methods in spatial_pooler.hpp
Removing obsolete .gitignore lines
Removing reverence to pbworks and syncEverything
Merge pull request #581 from oxtopus/cleanup-gitignore

Removing obsolete .gitignore lines
Merge pull request #580 from subutai/cppsp_docstring

Added initial documentation
Merge branch 'master' of github.com:numenta/nupic