Update to SimpleMIPS to use elftools, improved tracing, and new instructions

In the spirit of the new year, I am publishing some code that I have laying around on my workstation.

SimpleMIPS is an existing Python-based instruction set simulator for MIPS.  I wrote some code to replace its roll-your-own ELF parser with code from elftools library, to add simple for instruction trace generation, and add support for handful of new instructions.

Here is a link to my the repository : https://bitbucket.org/ecote/miss/overview