Upgrade support library. Switch gradle build tools and AS to 2.0. Adapt code to new support lib

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralFragment.kt

@@ -74,7 +74,7 @@ class SettingsGeneralFragment : SettingsNestedFragment() {
         if (preference === columnsPreference) {
             val fragment = LibraryColumnsDialog.newInstance(preference)
             fragment.setTargetFragment(this, 0)
-            fragment.show(childFragmentManager, null)
+            fragment.show(fragmentManagerCompat, null)
         } else {
             super.onDisplayPreferenceDialog(preference)
         }

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsNestedFragment.kt

@@ -1,5 +1,7 @@
 package eu.kanade.tachiyomi.ui.setting
 
+import android.app.FragmentManager
+import android.os.Build
 import android.os.Bundle
 import android.support.v14.preference.PreferenceFragment
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
@@ -40,4 +42,11 @@ open class SettingsNestedFragment : PreferenceFragment() {
 
     val preferences: PreferencesHelper
         get() = settingsActivity.preferences
+
+    val fragmentManagerCompat: FragmentManager
+        get() = if (Build.VERSION.SDK_INT >= 17) {
+            childFragmentManager
+        } else {
+            fragmentManager
+        }
 }

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsSourcesFragment.kt

@@ -71,7 +71,7 @@ class SettingsSourcesFragment : SettingsNestedFragment() {
             setOnPreferenceClickListener {
                 val fragment = SourceLoginDialog.newInstance(source)
                 fragment.setTargetFragment(this@SettingsSourcesFragment, SOURCE_CHANGE_REQUEST)
-                fragment.show(childFragmentManager, null)
+                fragment.show(fragmentManagerCompat, null)
                 true
             }
 

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsSyncFragment.kt

@@ -33,7 +33,7 @@ class SettingsSyncFragment : SettingsNestedFragment() {
                 setOnPreferenceClickListener {
                     val fragment = MangaSyncLoginDialog.newInstance(sync)
                     fragment.setTargetFragment(this@SettingsSyncFragment, SYNC_CHANGE_REQUEST)
-                    fragment.show(childFragmentManager, null)
+                    fragment.show(fragmentManagerCompat, null)
                     true
                 }
             }