Added a new mechanism for wads searching and downloading instead of GetWad - WadDownload
WadDownload is based on well-developed GetWad search algorithms, but has several advantages:
supports ftp, http and https protocols
saves (caches) the results, thus accelerating the subsequent search
allows to load all wads at the same time, in several ways
wad downloads occur in the background and do not interfere with the operation of other components
the game can be started automatically (if the download window is open and the corresponding setting is selected), or at the user's request
provides full control over the list of search sites
