Merge pull request #8 from ryanjdew/unstable

Functional option and safer operations
Update memory-operations-functional.xqy

Updated some of the doc
Merge branch 'unstable'
use transaction-map variable
update xray
Optimization to the ancestor intersect logic, reduced the number of calls to node-op:outermost significantly, and reduced the number of iterations that were occurring with tree placement
Throw an explicit error for passing nodes crossing document barriers #9
Fix typo in error message
rev version
improve performance of outermost #11
fix issue with namespaces moving #10
Cleanup the mem-op namespace that is added sometimes