[COMMON] improve config, common, and fileio for other environments

[EMU/OSD] improve lock_vm() and unlock_vm() to support nesting

[EMU/OSD] add force_unlock_vm() to force unlock vm ignoring nesting

[VM/DISK] improve for other environments

[VM/F9368] support F9368

[VM/FMGEN] fix to use FILEIO class (thanks Mr.Artane.)

[VM/LD700] improve for other environments

[VM/MC6809] improve for other environments

[VM/UPD765A] improve for other environments

[VM/V99X8] fix to check if screen buffer is valid or not

[WINMAIN] fix to check if button caption is multi-line or not

[VM/I8080] fix to use fetch_op() function to fetch opecode

[VM/I8080] support to read interrupt enabled status

[COMMON] improve common.h for other environments

[WIN32/SCREEN] fix crt filter issue for eFM-7