commitmonitor Code

Use the singleton class.

Check the pointer before accessing it.

Remove unneeded variables.

Use `empty()` instead of `size()` where possible.

Initialize variables and fix a resource leak.

Found by Coverity.

Patch from Björn Carlsson:
New option to scroll to earliest unread item, when project is selected

Store the last-checked revision in a separate variable when fetching the next few log messages so it can be used as the start revision. Also set the last-checked revision to zero so the 'limit' is used.
(Fixes issue #441) : Fetch next 100 inaccurate/does not work

* Search the changed paths as well when filtering
* allow to filter by multiple words, not just one
(Closes issue #430) : Enhancement request: smart filter

set pitch and family but leave font name empty: let the system chose the best font
(Fixes issue #438) : Korean output issue

(Closes issue #426) : Indentation of changed source lines