[cleanup] moved internal.h event functions to event.h

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[cleanup] removed unused utf8 strncpy function

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[cleanup] Minor event system cleanup

 - remove redundant fields from listener structure
 - merge redundant code paths in sgui_event_connect
 - fail if callback is NULL
 - remove excessively verbose comments
 - error checking in sgui_event_post
    - try resize queue
    - drop event if not possible
    - previously: assume allocation never fails,
      explode in your face if it does
 - minor simplifications in sgui_event_process

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[cleanup] Integrate doxygen generation into cmake buildsystem

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[cleanup] Generate WinDOS zip packge via cmake buildsystem

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
Add Unix installation targets to build system

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[fix] Fixed project description

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>
[cleanup] remove package script

Everyhing integrated into build system

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>