Explorer++

I have started to do some work on filters.
This patch is for:
1) added keyboard shortcut "Shift+F" to apply/remove filters
2) after a filter is applied/removed, the listview is refreshed to allow the items to be sorted correctly. Before, removing or changing the filter could have caused the items of the list to be out of order.
3) introduced a checkbox in the filter dialog to choose between case sensitive and case insensitive filters. Settings are indipendent for each tab.
4) fixed the filter string displayed when opening the filter dialog. Now the last filter string used for that tab is selected and displayed in the filter dialog combobox. Settings are indipendent for each tab.

I've committed the patch with a minor change - rather than refreshing the tab when the filter is applied, previously filtered items are inserted into their correct positions.

Hi David,
just checking the commit.

an additional note: in Explorer++\FilterDialog.cpp at line 62, the array TCHAR szFilter[256]; should acutally be 512 bytes long and not 256. My original patch 26 had a lenght of 100 bytes only, but on another patch not yet committed, I changed that to 512. The reason for that is that in Explorer.h the filter pattern is defined at line 111 as:
/* Filename filtering. */
TCHAR szFilterPattern[512];