Add InteractiveMacroConsole

[Technologicat]

unpythonic needs an advanced macro-enabled console for its hot-patching REPL, so it's possible to use all of unpythonic in the REPL.

Basically, it would be nice^TM to have feature parity with imacropy.console in something that runs like a regular code.InteractiveConsole.

Specifically:

• Any macro definitions imported during a REPL session should persist until the end of that session. Re-importing the same macro should overwrite the old binding.
• Macros should be help-able for interactive use, as in help(mymacro).

[Technologicat]

Added imacropy.console.MacroConsole, which does exactly this.

NOTE!

• The IPython extension module has been renamed; the module is now known as imacropy.iconsole, because the basic MacroConsole is more deserving of the module name imacropy.console.
• help(some_macro) sees the wrong docstring, both in the IPython extension and in MacroConsole. As a workaround, use imacropy.doc(some_macro), which works correctly, just like IPython's some_macro? does.