Fixes the following issues.
- Issue . Removes the pathauto validation step. Cleans up form handling.
- Issue by Les Lim, agentrickard, grndlvl; Allow existing records to be update instead of deleting and recreating them.
- Issue by CrashTest_, Les Lim, agentrickard; Adds js visibility to path fields for selected domains
- Issue by agentrickard, grndlvl: Rewrite of domain_path_paths to domain_path_lookup_path and loading paths progressively and caches them similar to drupal_lookup_path.
- Bug reported by apemantus. Use language variables properly and consistenly in path checks.
Note that we no longer perform path validation against pathauto.