fix setup.py to install pycrypto correctly

[thecodingshrimp]

Problem

zokrates_pycrypto is not correctly installed with pip install git+git://github.com/Zokrates/pycrypto since dependencies are not installed.

Reproduction

$ python3 -m venv venv
$ . venv/bin/activate
$ python3 setup.py install
$ python3
$ from zokrates_pycrypto.gadgets.pedersenHasher import PedersenHasher
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../zokrates_pycrypto/gadgets/pedersenHasher.py", line 2, in <module>
    import bitstring
ModuleNotFoundError: No module named 'bitstring'

Reason

setup.py did not include required packages from requirements.txt and therefore did not install the package zokrates_pycrypto correctly.

What changed

• bitstring==3.1.5 requirement was now added to setup.py
• .gitignore now features all possible python workspace files
• removed requirements.txt since it is replaced by setup.py