Start moving colors into themes

Using attrs instead of fixed colors it will be possible to style
everything and also dynamically grab the color where needed in code.
This is done with colorEmphasis as an initial test.

Also remove several unused colors.

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/KeyListFragment.java

@@ -28,6 +28,7 @@ import android.annotation.TargetApi;
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
+import android.content.res.Resources.Theme;
 import android.database.Cursor;
 import android.graphics.Color;
 import android.net.Uri;
@@ -46,6 +47,7 @@ import android.view.MenuItem;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup;
+import android.util.TypedValue;
 import android.widget.AbsListView.MultiChoiceModeListener;
 import android.widget.AdapterView;
 import android.widget.ListView;
@@ -675,8 +677,11 @@ public class KeyListFragment extends LoaderFragment
 
         private HashMap<Integer, Boolean> mSelection = new HashMap<>();
 
+        private Context mContext;
+
         public KeyListAdapter(Context context, Cursor c, int flags) {
             super(context, c, flags);
+            mContext = context;
         }
 
         @Override
@@ -705,9 +710,14 @@ public class KeyListFragment extends LoaderFragment
             // let the adapter handle setting up the row views
             View v = super.getView(position, convertView, parent);
 
+            TypedValue typedValue = new TypedValue();
+            Theme theme = mContext.getTheme();
+            theme.resolveAttribute(R.attr.colorEmphasis, typedValue, true);
+            int colorEmphasis = typedValue.data;
+
             if (mSelection.get(position) != null) {
                 // selected position color
-                v.setBackgroundColor(parent.getResources().getColor(R.color.emphasis));
+                v.setBackgroundColor(colorEmphasis);
             } else {
                 // default color
                 v.setBackgroundColor(Color.TRANSPARENT);

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/util/Highlighter.java

@@ -18,8 +18,10 @@
 package org.sufficientlysecure.keychain.ui.util;
 
 import android.content.Context;
+import android.content.res.Resources.Theme;
 import android.text.Spannable;
 import android.text.style.ForegroundColorSpan;
+import android.util.TypedValue;
 
 import org.sufficientlysecure.keychain.R;
 
@@ -44,9 +46,15 @@ public class Highlighter {
 
         Pattern pattern = Pattern.compile("(?i)(" + mQuery.trim().replaceAll("\\s+", "|") + ")");
         Matcher matcher = pattern.matcher(text);
+
+        TypedValue typedValue = new TypedValue();
+        Theme theme = mContext.getTheme();
+        theme.resolveAttribute(R.attr.colorEmphasis, typedValue, true);
+        int colorEmphasis = typedValue.data;
+
         while (matcher.find()) {
             highlight.setSpan(
-                    new ForegroundColorSpan(mContext.getResources().getColor(R.color.emphasis)),
+                    new ForegroundColorSpan(colorEmphasis),
                     matcher.start(),
                     matcher.end(),
                     Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);