Update todo.txt
Update files as being suggested by ruby_best_practices.
Merge branch 'master' into development

Conflicts:
	Gemfile
Increase colum size of filetype in attachments table.

Some M$ Powerpoint documents have a VERY long MIME type.
Update model and unit tests accordingly.
Speed up plotting of large 2d data sets by decimating vectors.
Update changelog.
Add possibility to export 2d CSV data also in DOS/Windows format (CR+LF).
Fix missing line end in Instancevalue#export2dData.
Extend unit test for CSV data export checking DOS format.