Make PythonConsole to be a Rich-Text editor

[Tucchhaa]

Problem:
Current PythonConsole has only basic functionality to type text and executing it.

Suggestion:
Add more features to make its usage more convenient, the features I suggest to implement are:

1. Syntax highlighting - Qt provides QSyntaxHighlighter to make implementation of syntax highlighting easier, we could use it.

2. Suggestion popup box - When user starts typing a popup should appear with suggestion. This popup should have items that are variable names, function names and class names which name contains or starts with the word the user just typed. Items can be parsed from the user's code and be provided from the pilot (like some global objects).

3. jupyter notebook-like output - Qt's TextEdit supports HTML tags for hyperlinks, images, tables. Using this functionality, the historyEdit could output not only text, but jupyter notebook-like output.

For now those are all the features I can think of for the PythonConsole. I think it's reasonable to implement this features one by one and in the suggested order. As result, pilot's code editor would become a convenient editor

[tigercosmos]

I like the idea. Let's do it?

[yungyuc]

Let's do it. Step by step.

[yungyuc]

Jupyter notebook's predecessor, ipython, has a Qt client. We can copy it.

We should use Qt for GUI. I do not want JavaScript before we have exhausted all desktop/native options.

A notebook-like interactive interface is good, but I also want a simple, terminal-like interactive environment is available.

Let's work out something and we discuss as we go.