Add K1n9 Duk3's IMF Player code fix and update the IMF Player.

[gerstrong]

Hi!

I found and fixed the bug that prevented your IMFPlayer from playing IMF files that use the OPL rhythm mode (Monster Bash is probably the only game that uses such files). Unfortunately, I used the IMFPlayer v2.0 source from sourceforge, not the current source from GitHub, so most of the fixes I made are probably useless. The only files that might be useful are dbopl.cpp and maybe dbopl.h.

The problem in dbopl.cpp were the default cases in the switch statements, which call the abort() function. I checked the DOSBox 0.74 source and noticed that there were no default cases at all, so I removed them and the IMFPlayer worked perfectly fine with rhythm-mode IMFs.

You can find my modified version of the IMFPlayer v2.0 source here:
http://k1n9duk3.k1.ohost.de/files/imfplayer_v21_src.zip

-- K1n9_Duk3

[gerstrong]

NY00123 also has some notes about it:

(09:38:36) ny00123: 1. Why I still hear that difference
(09:38:47) ny00123: 2. And why have I had issues trying to compile it as a standalone IMFPlayer update.
(09:39:02) ny00123: Well, should be simpler for you to hear, applying this test:
(09:39:27) ny00123: 1. Try loading Keen 9 and skip to level 8. If you don't have the cheats enabled for some reason, you can use the -tedlevel approach. Listen a bit.
(09:39:34) ny00123: I mean, in DOSBox, of course
(09:39:40) ny00123: 2. Retry the same but in CG.
(09:39:57) gerstrong: It's just different
(09:40:02) ny00123: Sure
(09:40:03) gerstrong: Hard to explain I guess.
(09:40:11) ny00123: Once you listen it will be very clear :)
(09:40:17) gerstrong: Okay, will do later.
(09:40:19) ny00123: Anyway, the standalone IMFPlayer (from GIT) is actually OK
(09:40:30) ny00123: (I mean from the "tools" directory)
(09:40:32) gerstrong: Because this issues needs to be fully adressed
(09:40:45) gerstrong: tools on the SF Page, right?
(09:40:48) ny00123: it's just the code in CG itself that messes up something.
(09:40:59) ny00123: I rather refer to "tools" as obtained from the GIT repository.
(09:41:07) ny00123: Probably not that different.
(09:41:11) gerstrong: okay.
(09:41:18) gerstrong: Will take that one and check.