Blender Git Loki

Keymap: resolve conflict with use_alt_cursor/Ctrl-LMB to add/extrude

While the option allows tools be be activated on press instead of tweak,
this meant box-select was catching Ctrl-LMB which is also used for
add/extrude in edit mode.

Resolve this by always using tweak for selection tools,
only supporting activation on press for other tools.

Note that this doesn't impact the default configuration.