typos and warnings

git-svn-id: http://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3834 ed541006-0bf7-43e9-8c4d-6fc63c346d47
Rework ListMidi so it can be more easily added to more backends.

git-svn-id: http://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3835 ed541006-0bf7-43e9-8c4d-6fc63c346d47
Rework ListMidi so it can be more easily added to more backends.

git-svn-id: http://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3836 ed541006-0bf7-43e9-8c4d-6fc63c346d47
Add midi.h to project file

git-svn-id: http://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3837 ed541006-0bf7-43e9-8c4d-6fc63c346d47