Merge tag '0.21' into develop

Bug fix release

field index calculation for multi-fields
Added links to upcoming talks
Added inline keyword to several free non-template functions
Added support for default values and result fields for insert
Added constraints that insert and update require some value specs
Made boolean expression more usable
Added bitwise_and and bitwise_or to integral
Added tvin arguments for parameters
Merge branch 'release/0.22'