documentation clean up - Githubissues

The installation pages make it more clear that you are installing both CMOR and PrePARE.
Added instructions for running the CMOR test suite in the Anaconda installation page.
Removed line about building with CDMS as the code for conversion of time values, cdtime, is part of the CMOR code.

These changes, and CMOR no longer requiring CDMS2, should close the following issue. Closes #97

PCMDI / cmor3_documentation