The method is not used for anything else than skipping tests for specific drivers. Cross-driver portability should be established by drivers, not outside of them based on their name.

Fixes #2953.

Allows result sets to be iterated over without running out of memory on
large data sets.

I am also of the opinion that the resource type checks are unhappy. We depend on driver internals.

* removed "charset" patch
* implemeted resource_type compare with in_array instead of regex
* implemented functional tests for connection and statement.

Revert "build a correct connection string for mirrored databases, too. In this case "host=ip1:port,ip2:port" servername and dbname are optional but can also be used without host parameter"

This reverts commit 0698cba6.

build a correct connection string for mirrored databases, too. In this case "host=ip1:port,ip2:port"
servername and dbname are optional but can also be used without host parameter

if $persistent=false, resource_type == 'SQLAnywhere connection'

References:
SQLA16 - http://dcx.sybase.com/index.html#sa160/en/dbadmin/serverport-network-conparm.html
SQLA12 - http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.11.0.1/dbadmin_en11/serverport-network-conparm.html