Intellisense: do not list empty schemas

[isc-tleavitt]

Compare:
select * from INFORMATION_SCHEMA.SCHEMATA

With:
select * from INFORMATION_SCHEMA.SCHEMATA s where exists (select top 1 1 from INFORMATION_SCHEMA.TABLES t where t.TABLE_SCHEMA = s.SCHEMA_NAME) or exists (select top 1 1 from INFORMATION_SCHEMA.VIEWS v where v.TABLE_SCHEMA = s.SCHEMA_NAME) or exists (select top 1 1 from INFORMATION_SCHEMA.ROUTINES r where r.SchemaUpper = s.SCHEMA_NAME)

The latter should be used.

[isc-tleavitt]

Actually, the issue in my case was that %SQL_MANAGER.ProceduresTree(0) lists schemas where subordinate items won't be suggested as tables. So fixing #33 for TVFs will fix this, and for the off chance that we have functions but no TVFs the impact is minimal.