Merge pull request #125 from geraldhumphries/master

More descriptive error messages, for when Steam is not found
added steam directory config entry
renamed pf to ph for platform_helper
Checks config.txt for configured Steam directory
Changed Steam Directory section to Steam and Steam parameter to Directory
Added config_steam_location to get Steam's directory from the config file, and changed the wording of some of the error messages to be more instructive.
Merge branch 'steamnotfounderr' of https://github.com/geraldhumphries/Ice into steamnotfounderr

Conflicts:
	ice/steam_installation_location_manager.py