BUG: Fixed exclusion list

Currently iris test coding standards will perform pep8 checks on files
contained within the build directory and then ignore the results.  This
commit removes this checking entirely and fixes a bug present in
generating the assumed directory for the iris repository from the iris
path (a problem which arises when considering softlink vs real paths).
Resolve PP save rule bug.
Merge pull request #892 from bjlittle/pp_save_unknown

Resolve PP save rule bug.
Merge pull request #893 from cpelley/pep8_test_build

BUG: Fixed exclusion list
Future context restores state even when interrupted.
Merge pull request #895 from pp-mo/future_fix

Future context restores state even when interrupted.
Test for single access
Avoid recursion and multiple reads in ABF loader