readme for src directory
updated directory structure to allow multiple languages (DE, EN, ES)
added license, resource-directory, logo
first version of gradle build (can compile ONLY the DE version, and only a single file
short (meaning: incomplete) version of EAP, containing only those chapters heavy on diagrams...

text-heavy chapters have been left out here!
started modularizing DE-version, updated build.gradle accordingly.
added kap03, kap04 to modularization