[launcher] D-Bus interface for upgrade status display in launchers
[launcher] Add support for temporary launcher items
[launcher] Update progress should only be shown on progress events
[dbus] Move well-known D-Bus names/paths to lipstickdbus.h

This makes it easier for external applications to use Lipstick via D-Bus
by depending on the devel package and using defined names from the
header file instead of hardcoding/copying the values everywhere.

Also makes sure that in case a D-Bus service name goes away or changes,
the depending code will either use the new name (by depending on the
header file) or fail to build from source, instead of just silently
failing at runtime.
[launchermodel] Cleanup D-Bus handling, temp launcher removal timer
[launchermodel] Documentation for the launcher model D-Bus API
[launchermodel] Fix a null pointer dereference for new icons
[launchermodel] Stop progress when D-Bus caller quits

Monitor all name owner changes on the D-Bus and remove in-progress
"updating" status of all launcher icons which had their updating
status initiated by the D-Bus service name that went away.
[launchermodel] Iterate over list of launchers in reverse order

Reduces best case time of lookups for new installations (icon is
appended at the end of the list) from O(n) to O(1). If looking up an
item in the list will become a bottleneck, we can do a hash over the
whole list with keys being the package name.
[launchermodel] Add heuristics for matching temporary launchers
[launchermodel] Call unsetTemporary() before each removeItem()
[launchermodel] Rename install -> updating in D-Bus API
[launchermodel] Temporary launcher matching heuristics updated

If there are more than one temporary item pick the one that's already
finished.
Implement feedback from code review
[launchermodel] Add simple unit test for updating a temporary icon
[launchermodel] Add two basic unit tests for launchermodel
Merge pull request #150 from thp/launcher-updating

Add D-Bus interface for showing install/update progress of apps