changed default config
major refactoring

modified types not to expect data structure and build display tree itself.
separated caching and http functions
separated slideshow sources

added network source (old functionality) as first available source
clock configs
catch socket timeout
take clock config to use
fix first slide update problem by adding initial slide
changed slidescene constructor to use slide object properly
changed filename/cachefile naming. Now only filename is valid and should contain path to file.
continued refactoring source handling
rewrote some debug prints (while debugging)