Removes hardcoded extension of PNG to allow OEM versions (qmg)

- adds unit-tests via two qmg files (one 9 patch, one regular)

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/ResFileDecoder.java

@@ -61,11 +61,11 @@ public class ResFileDecoder {
                 return;
             }
             if (typeName.equals("drawable") || typeName.equals("mipmap")) {
-                if (inFileName.toLowerCase().endsWith(".9.png")) {
+                if (inFileName.toLowerCase().endsWith(".9." + ext)) {
                     outFileName = outResName + ".9" + ext;
 
                     // check for htc .r.9.png
-                    if (inFileName.toLowerCase().endsWith(".r.9.png")) {
+                    if (inFileName.toLowerCase().endsWith(".r.9" + ext)) {
                         outFileName = outResName + ".r.9" + ext;
                     }