compile timetable from scratch each time, CI: produce both print and screen versions (only offer compressed pdf for screen)

- separate colors.tex, to include from any sub-document
- provide both rgb and cmyk versions
- use rgb by default, \def\colormodel{cmyk} for clean print version
- make timetable.sty work with all color specifications:
- new \defineeventcolors accepts 5 arguments: name, bg colorformat, bg color values, fg format, fg values
- new \leteventcolors accepts 3 arguments: name, name of previously defined color for bg, name of color for fg

modul: add multimedia/web, business processes, mobile roboter, bildverarbeitung, multimedia-anwendungen, forschungsprojekt, nebenläufige systeme, mobile anwendungen, we3, web design, auslandsmodule

modul: add buchführung, recht, W+I-math, management, rechnungswesen, wirtschaftsinformatik, softwarequalität, betriebliche informationssysteme, erp integration, empirische sozialforschung