Added a bunch of operator interpretations
Merge branch 'release/0.13'
Merge tag '0.13' into develop

Added a few helper types for the new connector
Switched remove to policy based design.

A lot of sweating to figure out how to do it, but now it looks MUCH
cleaner and it is probably a lot easier to extend :-)
Migrated select components to support policy based select
basic select methods work again

I've let go of the select(flags, columns) monster methods, these are now
separated
Removed the dreaded make_expression_tuple and make_flag_tuple
More reasonable dynamic limit and offset
Fixed possible dangling references problem
Fixed all_of use in select
Fixed multi_column to handle all_of again
Refactored insert to use policies

Much cleaner now.
Fixed a bunch of smaller migration errors
Added value type back to select
Corrected inconsistency in select value_type
Merge branch 'feature/policy-based-design' into develop
Added checks to prevent non-matching columns from being inserted