This patch revises the implementation of nitpicker in the following
respects:
- Split the implementation into smaller files,
- Consistently use the 'Nitpicker' namespace,
- Avoid the use of format strings,
- Retire old (and hackish) debug mode,
- Removal of unused timer connection,
- Merging 'Session' into 'Session_component',
- Merging 'Mode' into 'User_state',
- Adding the notions of 'View_owner' and 'Focus' as interfaces,
- Untangle 'User_state' and 'View_stack'
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082