(20583/21110) normalize --install, --type, --setup-dirs, --helpers

http://projects.puppetlabs.com/issues/20583 (`--install`, `--type`, and `--setup-dirs` are confusing)
https://projects.puppetlabs.com/issues/21110 (replace `--helpers` with ability to add libraries/includes)

Changes in this PR:
- remove --setup-dirs
- add --pre-suite and --post-suite, both can take files, directories or comma separated list of files and directories
- --type is reduces to be only 'pe' or 'git' and is only used to determine pathing
- adds --load-path to make additions to the LOAD_PATH before testing

This new setup will break currently running tests on Jenkins until they are updated with the new command line arguments.  The changeover shouldn't be too painful, but should be done during a slow time.