cmake: fixed UHD_IMAGES_DIR behavior to include directories inside specified images directory
Updated images downloader URL
Merge branch 'maint'

Conflicts:
	host/CMakeLists.txt
Updated master images downloader URL

Conflicts:
	host/CMakeLists.txt
Merge branch 'master' into next
docs: added info on libusbx for Windows
Merge branch 'maint'
Merge branch 'master' into next