JavaDoc Fixes

Fixed: Some JavaDoc issues.
Made the kernel program seriaziable

Fixed: The kernel program is now seriaziable.
Fixed: The process class will no longer compare executors in equals().
Merged develop into loadingbyte/sessions

Merged develop into loadingbyte/sessions because of required updates.
New session-packet

Added: There is now a new session-packet for everything related to sessions.
Profile Serializer session check

Added: The profile serializer now checks for open sessions which arent serializable.
Dynamic isSerializable()

Added: isSerializable() must now be answered by the session "executor" by overriding the method. That allows dynamic sessions which can be only serialized under certain conditions (like no widget is active).
Cleaned the desktop stuff

Fixed: Cleaned up the JavaDoc and the code of some things related to the desktop.
Fixed the profile serializer

Fixed: The profile serializer test is now working again. The actual serializer now tests if there's a root process avaiable for testing if there're sessions which can't be serialized.
Shell basics

Added: The basics for a shell! We added the basic session classes and will continue on with shell programs and the seperation of shell and desktop ones.