Dipsl

Fixed automatic PyPi release version number.

Besides some minor changes in documentation, this is a test of PyPi autorelease using GitHub Actions.

* added DIP parameter documentation extension for Sphinx
* added support for DIP interpreter language functions (function solver)
* allowed undefined modifications in imported sources
* introduced relative import of sources

Vrtulka23 proudly anounces the first release of PyDIPSL.