Please provide sane defaults for keyboard controls

[shankao]

Mednafen's keyboard controls can be configured by editing the ~/.mednafen/mednafen-09x.cfg file, but right now it needs to be done manually after installation, on every program run by pressing Alt+Shift+0 (to configure the controller number 0) or by passing the controls via command line parameters.

I suggest to improve the immediate usability of mednafen by adding some sane defaults in the config file out of the box. I'd go with the cursor keys for directions and, for the controller buttons, the common used keys in the corresponding emulators.
mess can be a good reference for standard keys too

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: mednafen 0.9.38.7+dfsg-1
ProcVersionSignature: Ubuntu 4.3.0-5.16-generic 4.3.3
Uname: Linux 4.3.0-5-generic x86_64
ApportVersion: 2.19.3-0ubuntu2
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Jan 13 10:00:10 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2012-11-25 (1143 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120627)
ProcEnviron:
 LANGUAGE=en_SG:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_SG.UTF-8
 SHELL=/bin/bash
SourcePackage: mednafen
UpgradeStatus: Upgraded to xenial on 2015-03-14 (304 days ago)