Can't get the icons to appear
I'm new to Android development, and your libraries have helped me to learn rapidly, thanks!

However I can't get the icons to show up. I followed the readme line by line, and tried both options in step 3, but couldn't get it to work. I tried to resort to `com.mikepenz.iconics.view.IconicsImageView` but no icon shows up.

This is my entire xml layout file
``` lang:xml
<?xml version="1.0" encoding="utf-8"?>
    <android.support.v7.widget.CardView android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/tools"
    android:id="@+id/cv"
    android:layout_margin="8dp"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:fresco="http://schemas.android.com/apk/res-auto">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >

        <com.facebook.drawee.view.SimpleDraweeView
            android:id="@+id/recipe_image"
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:layout_alignParentTop="true"
            fresco:placeholderImage="@drawable/recipe_placeholder"
            android:scaleType="centerCrop" />


        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/meal_setting_label"
            android:layout_below="@id/recipe_image"
            android:paddingTop="24dp"
            android:paddingStart="16dp"
            android:paddingEnd="16dp"
            android:paddingBottom="0dp"
            android:textColor="#222"
            android:textSize="24sp"
            />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/amount_recipe"
            android:layout_below="@+id/meal_setting_label"
            android:layout_marginTop="-12dp"
            android:padding="16dp"
            android:paddingTop="0dp"
            />

        <com.mikepenz.iconics.view.IconicsImageView
            android:layout_width="72dp"
            android:layout_height="72dp"
            android:layout_below="@id/amount_recipe"
            app:iiv_color="@android:color/holo_red_dark"
            app:iiv_icon="gmd-favorite" />

    </RelativeLayout>
</android.support.v7.widget.CardView>
```

I also added this to my Proguard file (no idea what it does, but I was browsing some closed issues that had this as the solve)

```
-keep class .R
-keep class **.R$* {
    <fields>;
}
```

These are in my gradle dependencies:
```
    compile('com.mikepenz:materialdrawer:5.8.0@aar') {
        transitive = true
    }

    compile 'com.android.support:appcompat-v7:25.0.1'
    compile 'com.android.support:cardview-v7:25.0.1'
    compile 'com.android.support:recyclerview-v7:25.0.1'
    compile 'com.android.support:support-v4:25.0.1'
    compile 'com.android.support:design:25.0.1'
    compile 'com.squareup.retrofit2:retrofit:2.1.0'
    compile 'com.squareup.retrofit2:converter-gson:2.1.0'
    compile 'com.squareup.okhttp3:logging-interceptor:3.3.1'
    compile 'com.facebook.fresco:fresco:0.14.1'
    compile 'com.jakewharton:butterknife:8.4.0'
    compile 'com.mikepenz:google-material-typeface:2.2.0.3.original@aar'
    testCompile 'junit:junit:4.12'
    apt 'com.jakewharton:butterknife-compiler:8.4.0'
```

I was hoping it's a rookie mistake :) Thanks in advance for the help
