GUAC-911: Separate parsing of level name into own function.
GUAC-911: Add and document log level option for guacd.
GUAC-911: Removing use of logging from libguac.
Merge branch 'master' into GUAC-844

Conflicts:
	src/libguac/user-handlers.c
GUAC-911: Add debug messages to common pieces dealing with guac_client.
GUAC-911: Log to STDERR always.
GUAC-911: Clean up logging in guacd.
GUAC-911: Greatly increase available values for guac_error. Remove use of guac_error by non-library code.
Merge branch 'master' into GUAC-844

Conflicts:
	src/common/guac_clipboard.c
	src/guacd/client.c
	src/libguac/client.c
	src/libguac/parser.c
	src/libguac/plugin.c