Prophy

-----------------------------------
- ci: dropping travis in favor or github-workflow
- python/gcc/clang versions updated

-----------------------------------
- prophyc: python codecs use relative imports proper for:
* in-package and out-of-package imports
* py2 and py3 language versions

-----------------------------------
- prophy: adding class comparison handlers for struct, union and enum
- prophyc: bitwise or in isar frontend bugfix
- prophyc: prophy backend docstring bugfix

-----------------------------------
- prophyc.generators.python: adding utf-8 encoding shebang
- prophyc.generators: prophy & python: reinforced unicode support for python2

-----------------------------------
- adopting to newer renew version: 0.4.1
- fixing ISAR unicode bug introduced in 1.2.0

warning for python2: this version had troubles generating python codec with unicode characters
please use 1.2.2 instead, works well with python3.x however

-----------------------------------
- prophyc.generators.prophy: introduced prophy language generator
- prophyc.generators.python:
* generated source code is pep8-compliant (at least much more than it was before)
* generated imports do not use asterisk, implicitly lists imported names
* generated file contains annotation about fact of being generated by prophy
- prophyc.parsers.isar collects docstrings
- prophyc.model:
* refactor performed, shaped nodes' inheritance tree
* each node gets reproducible repr() (added renew package as dependency)
* each node gets str implementation that returns its prophy language representation
* each node may have a doc-string
* node name and docstring can be defined in unicode (special care in python2)
* Constant can be defined with numbers in hexadecimal literal format

warning for python2: this version had troubles parsing XML's and generating python and prophy code
with unicode characters, please use 1.2.2 instead, works well with python3.x however