Uses src/iodbc headers rather than windows headers to hopefully standardize across...

Uses src/iodbc headers rather than windows headers to hopefully standardize across all platforms, and relieve dependency on <windows.h>
Now allows reading of unknown data table structures to create wxTable instances without knowing the data dictionary ahead of time (see wxColInf() class and use)
Ability to determine keys/foreign keys and read in those key definitions (see wxColFor() and wxDB::GetKeyFields() contributed by Mark Johnson)
More support for mySQL, now handles columns with "non-standard" types (contributed by Bart Jourquin)
SQLUnbind() was being called in some places which release ALL tables bound to the wxDB connection, not just the desired one
To fix the SQLUnbind() problem, now temporary datasource connections use GetData() rather than binding columns to variables (see wxDB::Catalog())
wxDB::Catalog() now handles databases that support, and do not support passing a UserID to limit the scope of the catalog
wxDB:TableExists() now handles databases that support, and do not support passing a UserID to limit the scope of existence check
"const char *" now used in the appropriate places rather than "char *"
GetDataSource() was not terminating the returned data source names with a '\0'
wxTable::Open() now more gracefully handles tables not existing but trying to be opened with more detailed error messages
wxTable::CreateTable() now handles return of SQL_SUCCESS_WITH_INFO as success (needed for some databases)
Fixes to accomodate 64bit archtecture handling of some data types (may not be totally ready for 64bit, but closer now).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@5546 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775