Update README with OSX installation instructions

[mik4el]

I got this excellent piece of software working without any problems on OSX together with the HackRF.

There are some stability concerns. The app crashes from time to time but the functionality is there.

Screenshot:

[RoninActual]

I have tried this approach multiple times but keep coming back to an AttributeError:
$ qspectrumanalyzer Traceback (most recent call last): File "/usr/local/bin/qspectrumanalyzer", line 7, in <module> from qspectrumanalyzer.__main__ import main File "/usr/local/lib/python3.7/site-packages/qspectrumanalyzer/__main__.py", line 5, in <module> from Qt import QtCore, QtGui, QtWidgets, __binding__ File "/usr/local/lib/python3.7/site-packages/Qt.py", line 1601, in <module> _install() File "/usr/local/lib/python3.7/site-packages/Qt.py", line 1553, in _install available[name]() File "/usr/local/lib/python3.7/site-packages/Qt.py", line 1049, in _pyside2 Qt.__binding_version__ = module.__version__ AttributeError: module 'PySide2' has no attribute '__version__'
I have tried uninstalling everything, including python and pyside2, and nothing seems to fix this. Any ideas?

[mik4el]

Sorry, I can't recreate your error :( And also please excuse a very late reply.

[ra1nb0w]

You can also find Soapy* on MacPorts.
Probably I can create a port for this too.

[ra1nb0w]

I see that this project doesn't receive commits from two years. not good ;-(