Added documentation to the helper functions

Also added invisible returns to some of them
Documented writeVWfile and added a return of the file path

As well as a default file path
Documented the vwCache function

Also put requirements in quotes, added vw_cache as an argument, and
added an argument to checkVW
Added docs to the vwControl() function
Added docs for the constructVW call function
Added docs for VW
Updated some docs
Rebuilt docs
Added loading of packages to the build script
Merge pull request #4 from zachmayer/vw_docs

Added documentation for the VW code