linux: look for legacy ~/.reicast and ~/.reicast/data
else look for ~/.config/flycast and ~/.local/share/flycast
and ~/.config/reicast and ~/.local/share/reicast
(defaults to flycast)
look for bios files in home folder and data folders (android, windows
,macos), then in game folder.
on linux, search in /usr/share/flycast and /usr/local/share/flycast and
legacy locations
store texture in the cache map instead of the heap
make related functions member of the class (CollectCleanup, killtex ->
Clear)
refactor common OSD stuff into rend/osd
vulkan support for OSD