* daemon: Handle new request B_MESSAGE_COMMIT_TRANSACTION. It activates
and deactivates given sets of packages. The new packages must be
placed in a directory in the administrative directory. The daemon
moves them to the packages directory and the deactivated packages to
a subdirectory it creates. It also save the old activation state
there.
* Add private BActivationTransaction, describing an activation change
transaction.
* BDaemonClient: Add CommitTransaction(), which sends a given
BActivationTransaction as a B_MESSAGE_COMMIT_TRANSACTION request to
the daemon.
Completely untested yet.
* Rename PackageDaemonDefs.h to DaemonDefs.h.
* Replace the MESSAGE_GET_PACKAGES by the new
B_MESSAGE_GET_INSTALLATION_LOCATION_INFO, which not only returns the
packages, but also other information about the installation location.
* daemon: Volume: Implement a change count which is bumped whenever
packages are activated/deactivated/added/removed. Cache the reply
for a location info request, using the change count to check whether
it is still up-to-date.
* Add private BDaemonClient for communication with the daemon.
* BRoster:
- Add GetInstallationLocationInfo() using BDaemonClient.
- Reimplement GetActivePackages(), using
GetInstallationLocationInfo().
