tdbc::odbc

* generic/tdbcodbc.c (GetCell, HasBigintMethod, ResultSetConstructor):
	Fix a crash where an error is returned from SQLGetData.
        Add a check for whether a connection supports 64-bit integers
	before trying to use them to replace NUMERIC or DECIMAL
	values. Add a method to determine 64-bit integer support.
	(Bug [8766b8dc40].)
* library/tdbcodbc.tcl (tdbc::odbc::connection typemap):
	Add to initialization a check for 64-bit integer support
	so that the above change works. (Bug [8766b8dc40].)

* generic/tdbcodbc.c (GetCell):
	(It is hoped) Fix a crash where an error is returned
	from SQLGetData. (Bug [8766b8dc40], partial fix.)
* tests/tdbcodbc.test:
	Code formatting changes to avoid long lines and spurious
	semicolons.

* generic/tdbcodbc.c (ResultSetNextresultsMethod):
* tests/tdbcodbc.test (tdbc::odbc-{30.6,31.1}:
	Made 'rowcount' work for multiple result sets. Added a
	test for 'rowcount' in multiple result sets, and added
	a rudimentary test that stored procedures can be called.
* library/tdbcodbc.tcl (tdbc::odbc::resultset preparecall)
	Added a non-executed sketch of how a preparse of
	a prepared statement call might go in order to allow
	the use of SQLProcedureColumns to determine parameter
	directions. (This code may or may not be used; a first
	experiment would simply be to make all SP parameters
	'inout' and see if that works.)

* tests/tdbcmysql.test:
	Added rudimentary test for 'nextresults' - the method
	is a dummy because the calls supported by tdbc::mysql
	do not allow for multiple result sets.

   * doc/tdbc_resultset.n:
	Added description of the 'nextresults' method,
	and its effect on 'allrows' and 'foreach'

* library/tdbc.tcl: Changed 'foreach' method on the connection, statement and result set objects so that 'foreach' and 'allrows' will iterate over multiple result sets. Added default 'nextresults' method (does nothing, reports that no further results are available) and 'outputparams' method (does nothing, reports no output parameters) to the base 'resultset' class so that drivers that lack multiple-results functionality need not implement these.