Removing most About windows and menu items as discussed here

http://www.freelists.org/post/haiku-commits/r40968-in-haikutrunksrcapps-activitymonitor-bootmanager-charactermap-codycam-deskbar,3
Leaving them for now in replicants, and in Terminal, according to (my interpretation of) the instructions here
http://dev.haiku-os.org/browser/haiku/trunk/src/apps/terminal/README.GPL_to_OBOS#L70
Some sporadic cleanup.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@41108 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/apps/mediaplayer/MainWin.cpp

@@ -27,7 +27,6 @@
 #include <stdio.h>
 #include <string.h>
 
-#include <AboutMenuItem.h>
 #include <Alert.h>
 #include <Application.h>
 #include <Autolock.h>
@@ -1476,12 +1475,6 @@ MainWin::_CreateMenu()
 
 	fFileMenu->AddSeparatorItem();
 
-	item = new BAboutMenuItem();
-	fFileMenu->AddItem(item);
-	item->SetTarget(be_app);
-
-	fFileMenu->AddSeparatorItem();
-
 	fFileMenu->AddItem(new BMenuItem(B_TRANSLATE("Close"), 
 		new BMessage(M_FILE_CLOSE), 'W'));
 	fFileMenu->AddItem(new BMenuItem(B_TRANSLATE("Quit"),