Improve reference to setFDKPaths

1. Give it the correct name.

2. Remove the reference to the line number, it is wrong and not worth
maintaining (the file is tiny and well commented)
Add some .gitignore files
Change comment about system Python

The setting given works on most systems, not just Ubuntu
Might as well copy the compiled xmlWriter.pyc as well
Clarify an instruction for those who aren't using a special Python build
Clarify MutatorMath installation instructions
Merge pull request #11 from rrthomas/master

Various small documentation fixes