Add an ibus-table-setup to set ibus table engine

The setup app can be accessed from:
  ibus Preferences -> Input Method -> select a method -> Preferences

The code and ui were adapted from

 * ibus-setup-pinyin
 * https://github.com/maxiaojun/ibus-table-setup
Setup: Add table information to About page
Merge remote-tracking branch 'mozbugbox/ibus-setup-table' into ibus-setup-table
Speedup sync_usrdb()

 * Remove unneeded commits
 * Clear in-memory mudb content once synced
 * return immediately if user_db is None (which means use in-memory db)
Save user database periodically to avoid data loss

Periodically sync mudb content to usrdb so we don't loss user created
phrase and freq when crash.

Currently the interval is set to 16 input ops or 30 seconds between
saving.
Update debian/ content
Avoid flashing by moving combobox renderer creation to front
Sync user db on engine destroy
Merge branch 'master' into ibus-setup-table-639

Conflicts:
	engine/main.py
Merge remote-tracking branch 'kaio/1.5.0' into save-user-db

Conflicts:
	engine/main.py
Merge remote-tracking branch 'kaio/ibus-setup-table-639' into save-user-db

Conflicts:
	engine/main.py
Input untranslated ascii directly when panel is empty

Some applications only accept directly input ascii as command input.
Character fed through xim commit will not work as intent.

When there were no candidates, we treated all the un-translated
(b/w half/full width) ascii chars as direct input chars.
Direct input ascii char for English mode on empty

Do the same input untranslated ascii directly when panel is empty for
the English mode.
Extract repeating code from _init_properties(self) to _new_property(self,key).
WIP: Removed excessive condition check on char eligiblity.
WIP: Jump right to later half of conditions when _mode isn't true.
WIP: Extracted more condition checks to dict.
WIP: Combined two dicts into single dict. Simplified the condition checks.
WIP: Removed excessive condition check.
Added back unicode string spec to condition check in _convert_to_full_width (self, c).