Added optional start index argument to Simulation.run

This will allow simulations to be run whilst skipping the first few
configurations, say if something breaks and you need to restart.
Added detail on configuration numbering to Simulation docstring.
Added basic code generator

This generator is still very much incomplete, but it's getting to the
point where it needs to be added to the repo.
Removed extraneous whitespace from Generator class
Removed unimplemented if statement.
Added import handling code

This code tells the Generator to skip imported modules when adding
locals from attribute objects.
Added brackets around binop return object.
Added optional start_indent argument to Generator.format
Added extra translation code to translate_funcs
Added augmented assign function to Generator class
Added tuple handling case in.
Added code to handle Eigen array indexing notation
Changed handling of append replacement in generator.
Added code to handle case of numpy zeros function calls.
Fixed some of the issues relating to array indexing in Generator
Added pre-existing member variables to Generator.members