Add routine to set CHistoryCombo case sensitive or not

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
For performance reason, only set URL and Find comboboxes case sensitive

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Fixed issue #1951: Slow switch/checkout dialog

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>