Fast updates  (#22)
Fast updates  (#22)

Merge based on  hettie-d/pg_bitemporal

* new update as select

* correction function fix

* tests fixes

* name fix

* tests order

* inactivate test fix

* short form of new correction function and more test fixes

* typo fix

* typo fix

* fixing empty array bug

* typo

* dealing with NULL array

* null issue

* dealing with NULL

* final fix for nulls

* adjusting tests

* test adj

* correction fix to accommodate corner cases

* change in test

* removing exception from ll_update

* bug fix in PG 10 update as select

scalegenius/pg_bitemporal,scalegenius/pg_bitemporal