Set language extension priorities per-project.
Added "reset-global-language-extensions-priorities" and "reset-project-language-extensions-priorities" commands.
Added FreeBASIC and QB64 syntax highlighting.
Fixed a minor bug that loaded the same language into memory multiple times.
Side Panel: Right click on a sub-directory and "Find in folder..." (SpartanJ/ecode#720).
File Save now defaults to the most recent save location (SpartanJ/ecode#734).
Side Panel: right click on a directory and open it on new window (SpartanJ/ecode#736).
Build and Run: fix run in terminal on Windows 8.1 (SpartanJ/ecode#740).
Added a new UIMessageBox event: `Event::OnDiscard`, this will triggered when window is closed without confirmation (`Event::OnConfirm`). And now `Event::OnCancel` is only triggered when is manually cancelled (click the cancel button).
ecode: Greatly improved image viewing experience. Now you can switch images from the same directory with the mouse wheel, also zoom, translate and rotate the images, images open in a new tab by default but quick-preview can be activated in `Settings -> Window -> Quick Preview Images` (SpartanJ/ecode#96).
