Fertigstellung der zweiten Aufgabe
Added the course notes for the Session 04.
Ignored the data folder.
Typos.
Added a scaffold for the session.
Solutions for the Session 05.
WWD2
Merge branch 'master' of https://github.com/arbox/R_Course_2014-15

Conflicts:
	Session_04_2014-11-18/working_with_data_II.Rmd
Merge branch 'master' of https://github.com/d3fault/R_Course_2014-15