drush 6.x-4.0-rc5

Changes since DRUPAL-6--4-0-RC4:

• Add docs for --watchdog global option.
• #1007148 by greg.1.anderson: Make drush_choice and drush_print_file respect non-interactive modes
• #1007360 by greg.1.anderson: include updatecode.pm.inc
• #1007380 by greg.1.anderson. drush pm-enable cannot be hooked by commands that are being enabled.
• Document the show-invoke global option.
• Update site-upgrade for recent changes in pm code. I removed a cache clear from updatedb on D7. We should be on the lookout for ill consequences.
• #784940 by moshe weitzman. Let dd %files work on D7.
• #1008136 Strict warning for filesystem paths
• #784940 by greg.1.anderson. drush core-cli improvements.
• Slight optimization in sitealias code. I admit that I am not 100% clear on when this gets called.
• #983914 by moshe weitzman. rollback of http://drupal.org/cvs?commit=463994.