Some institutions may prefer. (Not been thoroughly road tested.)
- Mostly accounts for SQL differences and sqlalchemy:
	- exists not allowed in columns clause of select
	- boolean as BIT (is True, casting etc.)
	- tuple comparison
	- group by must include all returned columns
	- don't assume case sensitivity (depends on collation setup)
	- can't use Text without a length if setting unique, conversely
	  Text() in postgresql doesn't accept a length, use String
	- CheckConstraint passes string verbatim and therefore has
	  "limited database independent behaviour".  Switch to
	  enforcing at app level
- some threading issues during tests not seen in other DBMSs
- Test MultiprocCounter against provided database unless using an
  in-memory sqlite db (in which case switch to a temp file)

+ GenericExporterTests - fix occasional fail on datetime type tests
  i.e. when test runs over the second (seems more common using my
  current docker MSSQL setup)
+ some bits and pieces

NOTE:
- end user may still need to install a driver:
  osx - HOMEBREW_ACCEPT_EULA=Y brew install msodbcsql17 mssql-tools
  windows - download and install VC_redist.x64.exe
- pyodbc mingw windows awaiting mkleehammer/pyodbc#1169