Added new button style and converted account_settings and the select_secret_key_layout to use it

OpenKeychain/src/main/res/drawable/button_edgy.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:state_pressed="true" >
+        <shape android:shape="rectangle"  >
+            <padding
+                android:bottom="6dip"
+                android:left="6dip"
+                android:right="6dip"
+                android:top="6dip" />
+            <stroke android:color="#cccccc" android:width="1.5dip" />
+            <stroke android:color="#ebebeb" />
+        </shape>
+    </item>
+    <item android:state_focused="true">
+        <shape android:shape="rectangle"  >
+            <padding
+                android:bottom="6dip"
+                android:left="6dip"
+                android:right="6dip"
+                android:top="6dip" />
+            <stroke android:color="#cccccc" android:width="1.5dip" />
+            <solid android:color="#ebebeb"/>
+        </shape>
+    </item>
+    <item >
+        <shape android:shape="rectangle"  >
+            <padding
+                android:bottom="6dip"
+                android:left="6dip"
+                android:right="6dip"
+                android:top="6dip" />
+            <stroke android:color="#cccccc" android:width="1.5dip" />
+            <solid android:color="#ffffff" />
+        </shape>
+    </item>
+</selector>

OpenKeychain/src/main/res/layout/api_account_settings_fragment.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:bootstrapbutton="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     xmlns:custom="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
@@ -43,7 +42,7 @@
         android:layout_height="wrap_content"
         tools:layout="@layout/select_secret_key_layout_fragment" />
 
-    <com.beardedhen.androidbootstrap.BootstrapButton
+    <Button
         android:id="@+id/api_account_settings_create_key"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
@@ -52,9 +51,9 @@
         android:layout_marginRight="4dp"
         android:layout_marginTop="4dp"
         android:text="@string/api_settings_create_key"
-        bootstrapbutton:bb_icon_left="fa-key"
-        bootstrapbutton:bb_size="default"
-        bootstrapbutton:bb_type="default" />
+        android:background="@drawable/button_edgy"
+        android:drawableLeft="@drawable/ic_action_accounts"
+        android:textSize="14dip"/>
 
     <org.sufficientlysecure.keychain.ui.widget.FoldableLinearLayout
         android:layout_width="match_parent"

OpenKeychain/src/main/res/layout/select_secret_key_layout_fragment.xml

@@ -1,11 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:bootstrapbutton="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:orientation="horizontal">
 
-    <com.beardedhen.androidbootstrap.BootstrapButton
+    <Button
         android:id="@+id/select_secret_key_select_key_button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
@@ -14,9 +13,9 @@
         android:layout_marginRight="4dp"
         android:layout_marginTop="4dp"
         android:text="@string/api_settings_select_key"
-        bootstrapbutton:bb_icon_left="fa-key"
-        bootstrapbutton:bb_size="default"
-        bootstrapbutton:bb_type="default" />
+        android:drawableLeft="@drawable/ic_action_accounts"
+        android:background="@drawable/button_edgy"
+        android:textSize="14dp"/>
 
     <LinearLayout
         android:layout_width="match_parent"