implement Update1 & Update8 LDBC queries for API connector
add update2 api implementation
better json plan serialization
Merge branch '2.0-maint' into 2.1-maint
Merge branch '2.1-maint'
use 'profile' on first execution of a query, to gather plan description with more db hits
Merge branch '2.0-maint' into 2.1-maint
Merge branch '2.1-maint'