Started work on map window
map window basic stuff done
map widgets + identified spinner widget
sprite id error
map window work + identified window var 4AC (selected tab idx)
map window paint method
Merge branch 'ddevrien-map-window'
renamed strings.[ch] to string_ids.[ch] due to name collision
fix warnings
use POSIX functions if applicable; macro switches for windows-specific code
added CMakeLists.txt
new cpuinfo function to query CPU features
added MinGW compatible ASM code
fixes to execute a mingw-compiled openrct2