Merge tag '0.6' into develop

Release 0.6

Mainly a bug fix release (insert did not work at all).
Added link to postgreSQL connector
Added serializable_list (which is a noop for non-dynamic cases)
Prevent template constructor to overload default copy cosntructors
Use serializable_list in update and insert
Prevent template constructor to overload default copy constructors
Remove clang warning for in() and is_null()
Minor cleanup
Merge branch 'release/0.7'