[REFACTOR|INTERNAL] code cleanup in SarosSession class

Merged / inlined methods.
Renamed handleFileAndFolder method.

Changed some log statements.

setPermission method now performs the correct synchronization by itself.

Change-Id: I3a887976fbcccb2e00902e883ed8db4512e88f01
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1041
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>