67699: all your nsIClassInfo is belong to us

- teach nsGenericFactory about nsIClassInfo, and nsIClassInfo.idl to the
  builds
- add a heaping serving of macro love for classes that want to support it
- convert many modules to use nsGenericModule the new way
- handful of warning and modeline fixes
- nsSample and some XPConnect test classes now have nsIClassInfo support for
  testing

xpcom/sample/program/nsTestSample.cpp

@@ -33,7 +33,8 @@
 
 #define NS_SAMPLE_CONTRACTID "@mozilla.org/sample;1"
 
-main()
+int
+main(void)
 {
     nsresult rv;