maintain: add format lib as submodule

Unfortunately my original fork of format has been lost. Recreate
the changes in format to get Swivel running again. These changes
include:

 * Parsing of StartSound and SoundStream tags
 * Handling of LZMA compressed SWFs

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "lib/format"]
+	path = lib/format
+	url = https://github.com/Herschel/format

Swivel.hxml

@@ -3,8 +3,8 @@ com.newgrounds.swivel.Swivel
 -cp src
 -cp huey/src
 -cp huey/test
+-cp lib/format
 -lib air3
--lib format:3.3.0
 -main com.newgrounds.swivel.Swivel
 -swf bin/Swivel.swf
 -swf-header 930:590:30

Swivel.hxproj

@@ -17,6 +17,7 @@
   <classpaths>
     <class path="src" />
     <class path="huey\src" />
+    <class path="lib\format" />
   </classpaths>
   <!-- Build options -->
   <build>
@@ -30,7 +31,6 @@
   <!-- haxelib libraries -->
   <haxelib>
     <library name="air3" />
-    <library name="format:3.3.0" />
   </haxelib>
   <!-- Class files to compile (other referenced classes will automatically be included) -->
   <compileTargets>