Mavscript 2.0.0 released

This release provides the recent version 1.4 of the algebra system Yacas.

Changes:
- Default control character set to § (§m, §i, §io, §o, §n).
- The previously used dollar char is available using the option --controlchar $ (or -D$).
- Yacas 1.4.2 --> native unicode support (for all platforms)
- mavscript-yacas transfers unicode chars to yacas, without parameter --ascii (Windows too).