[dialog]
fixed a bug in /xdialog -E where -c flag wasn't being handled.
[general]
changed more lstrcpyn() calls to dcx_strcpyn()
added dcx_ConChar() macro for use when a "1" or "0" result is required.
changed code to use this new macro.
changed more code to use the dcx_Con() macro.
reworked the dcx_Con()/dcx_ConRet()/dcx_ConRetState() macros.

[listview]
added a small workaround for extreme slowness when working with huge lists & not using progressbars.
fixed bug that caused subitem selection to fail when the click event was disabled.
reworked UpdateScrollPbars() & ScrollPbars() to be a little bit faster.