Used Item attribute getters introduced by 10.4
Make changes to support Item::CONST_ITEM introduced by 10.4
as a replacement for INT_,REAL_,STRING_ ITEM.
Replaced QT_INFINIDB_DERIVED and similar flags
with correponded flags for Item->print().
Replaced or commented out infinidb_ variable names with columnstore_
where applicable.
SELECT_LEX had been moved in THD so changed all references.
Avoid writing CS decimal scales into MDB decimal fields
d-only dec attribute. WIP
Replaced infinidb_vtable with a singleton MIGR.
Merged with MCOL-2121.
Added new wsrep include paths needed by UDaF code.
Removed .vcxproj from Connector code.
Renamed isInfiniDB() into isMCSTable
Changed getSelectPlan() to reuse it with derived and
other handler types.
Separate pushdown handlers methods and functions.
Removed vcxproj files from the source.
Added fix for MCOL-2166.
Merged with MCOL-2121