Fixes and new API additions.

• Includes Go cleanup.
• New .Each iteration method.
• Locking semantic fixes.

Fixes to locking and OrderedPair

• Includes fixes to deadlock
• Robustness around locking
• The exporting of OrderedPairs.

v1.5: Merge pull request #26 from Vector919/spelling_fix

quick typo fix for cartesian product README updates