0.6pre1 - introduce the final changes

- implement E1xy/E2xy Defle bug when using same note twice
- add SNK Touchdown Fever preset
- update README.md and to-do list
- update credits

thank you for your patience!

see you in 0.6pre1.5 coming soon...

src/gui/about.cpp

@@ -108,9 +108,10 @@ const char* aboutLine[]={
   "Portable File Dialogs by Sam Hocevar",
   "Native File Dialog by Frogtoss Games",
   "RtMidi by Gary P. Scavone",
+  "FFTW by Matteo Frigo and Steven G. Johnson",
   "backward-cpp by Google",
   "adpcm by superctr",
-  "Nuked-OPL3/OPLL/OPM/OPN2 by Nuke.YKT",
+  "Nuked-OPL3/OPLL/OPM/OPN2/PSG by Nuke.YKT",
   "ymfm by Aaron Giles",
   "MAME SN76496 by Nicola Salmoria",
   "MAME AY-3-8910 by Couriersud",
@@ -131,7 +132,7 @@ const char* aboutLine[]={
   "VICE VIC-20 sound core by Rami Rasanen and viznut",
   "VERA sound core by Frank van den Hoef",
   "K005289 emulator by cam900",
-  "Namco 163 emulator by cam900",
+  "Namco C163 emulator by cam900",
   "Seta X1-010 emulator by cam900",
   "Konami VRC6 emulator by cam900",
   "Konami SCC emulator by cam900",