relax SVN archive

The py2app part of the setup.py script now throws a RelaxError if the setuptools module is missing.

Added the relax prompt icon to the main GUI window toolbar.

Added the larger sized application-x-executable-script Oxygen icons.

The relax GUI is now robust and able to withstand a call to the reset user function.

This could have occurred if the user ran a script with a reset() call, or if reset() was typed at
the GUI version of the relax prompt.

The ANSI ending escape sequence is now always placed before the last newline.

This fixes some weirdness of the cursor or other parts being coloured when they should not be.

The script ANSI colour is now cyan to fit better into the relax blue/black colour theme.

Fix for the GUI interpreter when turning off the ANSI codes of the relax prompt.

Better control of the relax prompt colouring via ANSI escape sequences.

The new Exec_info.prompt_colour_on() and Exec_info.prompt_colour_off() methods are now used to turn
the colours on and off by aliasing the coloured or non-colours prompts to both the class instance
namespace and to the sys module.

Shifted the script colouring ANSI escape sequences into the 'ansi' module.

Fix for a typo in r15769.