Pyqtconsole

- fix TypeError in highlighter when called without formats

- fix AttributeError due to QueuedConnection on PyQt<5.11 (23)
- fix exception on import when started within spyder (26)
- fix gevent example to incorporate interoperability code for gevent/Qt (28)
- fix not waiting for empty line when entering code blocks before applying input (30)
- fix TypeError during compilation step on python 3.8
- allow user to override syntax highlighting color preferences (29)
note that this is provisional API
- automate release process (34)

- fixed indentation and autocomplete conflict (74)
- replaced ``QRegExp`` for compatibility with QT6 (76)

- fixed PyQt warning because of explicit integer type
- fixed jedi autocomplete because of method rename

- add PySide2 compatibility
- add Ctrl-U shortcut to clear the input buffer
- use standard QtPy package to provide the compatibility layer
- hide the cursor during the execution of a python command
- mimic shell behaviour when using up and down key to go to end of history
- fix crash when closing the interpreter window of the threaded example
- disable excepthook on displaying exception
- write '\n' before syntax errors for consistency

Thanks to roberthdevries and irgolic for their contributions!

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