This commit tackles the more difficult-to-fix warnings that -Wmissing-field-initializers reported. I've compares the new tables in TrackData with the old ones through a script to make sure they are in fact the same.

Verify compilability of headers on Travis v2

This will skip linking step

Using approach described in
https://github.com/OpenRCT2/OpenRCT2/pull/7369#issuecomment-393973857
with updates to ease readability and maintenance.

Submitted as different PR, to keep history of the old approach.
Supersedes #7369.

Updates for CMakeLists

This should now work after many changes to upstream

Remove unused function

Last call was removed in 66a6aa95

Refactor OpenSSL usage

Make widget spinners horizontal