Changes in the ipynb and add of EM codes

*add of /files to pictures, needed for ipython version 1.#
*new folder with codes from challenges from 01_01_Phugoid_Theory
 and 01_02_Phugoid_Oscillation
*The pdf files are the images generated by the codes
Merge branch 'master' of https://github.com/ncclementi/numerical-mooc