Fix #109 - Added doc/parameter_files subdir; Also added piControl json install
Merge pull request #178 from durack1/issue109_durack1_CreateDocParamFilesSubdir

Issue109 durack1 create doc param files subdir

@gleckler if you update your CMIP5 amip/hist/piControl parameter files into the doc/parameter_files subdir in the repo, these will get copied into doc/parameter_files upon installation
Merge branch 'pcmdi_master'