Fixed #1190: Wrong sorting of motion identifier

- Added natural sorting JS plugin for motion DataTables (column identifier).
- Added the new requirements python package 'natsort' for natural sorting of motions in PDF.
Merge pull request #1192 from emanuelschuetze/naturalsort

Fixed #1190: Wrong sorting of motion identifier
Fixed #1138: Wrong file for projectors logo
Merge pull request #1207 from emanuelschuetze/fix-1138

Fixed #1138: Wrong file for projectors logo
fix for python2.6 and pip 1.5
Merge pull request #1218 from ostcar/argparse_fix

Fix for Python 2.6 and Pip 1.5 (use of argparse 1.2.1)