vcs: Pass registry to vcs for user authentication. Explicit pass the registry insted of indirectly using it via pyramids thread locals.

config: Use hooks protocol and direc calls seting from vcs settings module.

vcs: Raise an error in case of unsupported protocol.

config: Move vcs hooks protocol and direct call setting to vcs configure mehod.

config: Update config files with comment about 'vcs.backends' setting.

config: Sanitize 'default encoding' setting.

config: Sanitize vcs realted settings during pyramid app init.

config: Add method to sanitize string values from ini file.

config: Add method to sanitize list values from ini file.

vcs: Move the setup code for vcs lib from pylons to pyramid layer. The VCS setup code now uses the prepared settings from pyramid layer.