MAME 241, New Alert UX, ROMLESS Machines, Custom (non Software List) SOFTWARE and ROMs

This PR does three major things...

MAME 241 (normal update and core changes to enumerate romless machines)
- note romless machine enumeration is still too slow, need to fix.
New Alert UX, combined the Alert and InfoHUD classes, and converted to Swift. based on work started for PV.
- new UX is much nicer (especially on tvOS) and was needed when we show large lists to let user pick Machine to run.
Import and run non-SoftwareList software (ie ROMs and DISK images)
- This required a MAME core change to surface the machine metadata for file extensions.
- The list of file extensions imported by the app is listed in the Info.plist, other file types can by manually copied to the software directory.
see WHATSNEW for a list of romless Machines and Consoles

yoshisuga / MAME4iOS