Install some more headers useful in homescreen implementations
Bump version
Use a specific name for the notification manager database connection to allow other connections
Fix check for _NET_WM_STATE_SKIP_TASKBAR

The property was never checked in reality.
Request properties in one go

Two calls are not needed. Based on review, request only 12 properties.
Also, added a missing XFree.
Merge pull request #33 from mikkoharju/skip-taskbar

Fix check for _NET_WM_STATE_SKIP_TASKBAR
Bump version
Add a possibility to remove all user removable notifications
Bump version