Minor cleanup related to tab widths.

Made use of plain text consistent.

First pass of input syntax transformation support

Add test for missing input encoding. Back to 100% coverage.

Setting the input buffer now respects HTML continuation prompts.

* Moved AnsiCodeProcessor to separate file, refactored its API, and added unit tests. * Improved traceback display. * Modified FrontendWidget to use tabs instead of spaces for convenient deletion.

* IPythonWidget now has IPython-style prompts that are futher stylabla via CSS * Added support for HTML to ConsoleWidget * General cleanup and refactoring.

Added banners to FrontendWidget and IPythonWidget.

Kernel subprocess parent polling is now implemented correctly for Unix.

Kernel subprocess parent polling is now implemented for Windows.