Drawerfix/readme update (#601)

* Fixed back button on navigational drawers

* Removing an unused import

* Cleaned up code

* little clean up

app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

@@ -93,7 +93,9 @@ class MainActivity : BaseActivity() {
 
     override fun onBackPressed() {
         val fragment = supportFragmentManager.findFragmentById(R.id.frame_container)
-        if (fragment != null && fragment.tag.toInt() != startScreenId) {
+        if (drawer.isDrawerOpen(GravityCompat.START) || drawer.isDrawerOpen(GravityCompat.END)) {
+            drawer.closeDrawers()
+        } else if (fragment != null && fragment.tag.toInt() != startScreenId) {
             if (resumed) {
                 setSelectedDrawerItem(startScreenId)
             }
@@ -140,4 +142,4 @@ class MainActivity : BaseActivity() {
     companion object {
         private const val REQUEST_OPEN_SETTINGS = 200
     }
-}
+}