Release Name: 1.5

Notes:
Release 1.5 of Tioga now ships with the images used for help and tutorial, which makes the archive significantly bigger. Try out the -without-images one if you plan looking at the web documentation.

Apart from that, this release didn't see significant changes, save the return of the base for MacOS GUI and some portability fixes.


Changes:
* some portability fixes
* the return of maker.rb
* Function#derive
* FigureMaker#create_temp_files is now public
* some sample improvements