Updated terrain type icons to provide them with a transparent background

This commit is a follow-up of 82b8d9ecdf5c0f7121703e34acfe8f95ea9ae489
The updated 16x16 terrain type icons need to be wired with the 16x16 TC-able icon base so that the status info works properly.
30x30 icons are provided for a future use in high-res displays, where they should be overlaid on top of the 32x32 TC-able icon base