remove all prebuilt jars

This gets rid of all prebuilt jars in the repo.

* libs/disklrucache-2.0.2.jar doesn't seem to be used anymore, app builds
  fine when removing it.
* libs/touch-image-view.jar is indeed required but is not anywhere available
  via gradle. So instead we include the source of this long unmaintained
  library directly.

build.gradle

@@ -185,7 +185,6 @@ android {
 
 dependencies {
     /// dependencies for app building
-    implementation name: 'touch-image-view'
     implementation 'com.android.support:multidex:1.0.2'
     compile 'com.github.nextcloud:android-library:1.0.31'
     implementation "com.android.support:support-v4:${supportLibraryVersion}"

src/main/java/com/ortiz/touch/ExtendedViewPager.java

@@ -0,0 +1,34 @@
+package com.ortiz.touch;
+
+import android.content.Context;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.view.View;
+
+
+public class ExtendedViewPager extends ViewPager {
+
+	public ExtendedViewPager(Context context) {
+	    super(context);
+	}
+	
+	public ExtendedViewPager(Context context, AttributeSet attrs) {
+	    super(context, attrs);
+	}
+	
+	@Override
+	protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
+	    if (v instanceof TouchImageView) {
+	    	//
+	    	// canScrollHorizontally is not supported for Api < 14. To get around this issue,
+	    	// ViewPager is extended and canScrollHorizontallyFroyo, a wrapper around
+	    	// canScrollHorizontally supporting Api >= 8, is called.
+	    	//
+	        return ((TouchImageView) v).canScrollHorizontallyFroyo(-dx);
+	        
+	    } else {
+	        return super.canScroll(v, checkV, dx, x, y);
+	    }
+	}
+
+}