Blackmamba

* New tab shortcut changed to `Cmd-T` (reported by Ole)
* Open quickly shortcut synced with Xcode to `Cmd-Shift-O` (reported by Ole)
* `Ctrl-Shift-B` to clear annotations & analyze file (bundled pyflakes)

* Allow to specify folders to ignore for Run/Open Quickly... via `blackmamba.settings`
* `Run Script Quickly...` renamed to `Run Quickly...`
* New `blackmamba.ide` functions - `run_script`, `script_exists`, `run_action`,
`action_exists`
* `key_commands.register_key_command` prints shortcut in a nicer way along with package
& function name