SHP/SDF: fix various Select/SelectAggregates defects

[pierre.dalcourt@…]

Fixed these SHP/SDF defects

SDF: SELECT AGGREGATE FUNCTIONS EXECUTED ON INVALID DATA TYPES FOR THAT FUNCTION RETURNS A 0.0 VALUE.

SDF: SELECT AGGREGATE FUNCTION MIN AND MAX ON A DATETIME DOES NOT RETURN A VALID VALUE.

SDF: SELECT AGGREGATE FUNCTION MAX AND MIN ON A STRING DOES NOT RETURN A VALID VALUE

SHP: CERTAIN SELECT AGGREGATE FUNCTIONS CAUSE ERROR "FETCHING A PROPERTY VALUE DID NOT MATCH THE PROPERTY TYPE"

SHP: Select using computed field and aggregate function is not supported but fails to generate an exception

Other issues addressed

• Added Min/Max(string/datetime) support to SDF and SHP, by adding this to FdoCommonQueryAggregator
• Added full TestCommon support to SDF and SHP unit tests; increased usage of TestCommon in many places
• Improved error handling in SDF/SHP unit tests (Several tests werent catching/reporting errors correctly)
• ShpSelectCommand now validates upfront that you are not using aggregate functions or invalid arguments to functions (e.g. Ceil(String))
• SDF: added SchemaTest.* to OpenSource tests (it doesn't rely on Sdf.lib)
• improved FdoCommonDataReader::GetAggregateFunctions() to handle NULL select list
• added 3 new TestCommon classes and moved some generic SHP/SDF utilities to them (see Note To Developers)
• moved some more stuff to TestCommonMiscUtils (see Note To Developers)