Updated all default OPKs (better icons, updated descriptions...) and default GMenu2X theme "DrUm3x3" with 3x3 grid instead of 2x2 + extra theme "DrUm3x4"

Added Libretro OPK for GMenu2X users in "Games" section

FunKey/package/picodrive/opk/megadrive/megadrive.funkey-s.desktop

@@ -1,12 +1,8 @@
 [Desktop Entry]
-Type=Application
-Name=MegaDrive
-Comment=Sega Genesis/MegaDrive Emulator
+Name=Mega Drive
+Comment=SG/SMS/GG/MD/MCD/32X emulator
 Icon=megadrive
 Exec=/usr/games/launchers/megadrive_launch.sh %f
-Terminal=false
-X-OD-NeedsDownscaling=true
-Categories=emulators;
-selectorbrowser=true
+Categories=emulators
 SelectorDir=/mnt/Sega Genesis
-SelectorFilter=zip,ZIP,md,MD,bin,BIN,32x,32X,cue,CUE,cso,CSO,chd,CHD,smd,SMD
+SelectorFilter=zip,ZIP,md,MD,bin,BIN,32x,32X,cue,CUE,cso,CSO,chd,CHD,smd,SMD,gg,GG,sg,SG

FunKey/package/picodrive/opk/sms/SMS.funkey-s.desktop

@@ -1,12 +0,0 @@
-[Desktop Entry]
-Type=Application
-Name=Master System
-Comment=Sega Master System Emulator
-Icon=sms
-Exec=/usr/games/launchers/sms_launch.sh %f
-Terminal=false
-X-OD-NeedsDownscaling=true
-Categories=emulators;
-selectorbrowser=true
-SelectorDir=/mnt/Sega Master System
-SelectorFilter=zip,ZIP,sms,SMS,bin,BIN