Separate safety number camera image into a separate image view so it can be properly centered.

Insted of using fixed image and text insets to try to center this image,
split the image out into a separate view and center it properly using a
constraint.  Touches still pass through to the button underneath.

Fixes #1622.  FREEBIE

Signal/src/Storyboard/Main.storyboard

@@ -249,19 +249,22 @@
                                         <nil key="highlightedColor"/>
                                     </label>
                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="top" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="RX6-CJ-FV1">
-                                        <rect key="frame" x="117" y="207" width="141" height="70"/>
+                                        <rect key="frame" x="143" y="207" width="89" height="70"/>
                                         <constraints>
                                             <constraint firstAttribute="height" constant="70" id="g0E-XL-o8K"/>
                                         </constraints>
-                                        <inset key="titleEdgeInsets" minX="-50" minY="44" maxX="0.0" maxY="0.0"/>
+                                        <inset key="titleEdgeInsets" minX="0.0" minY="44" maxX="0.0" maxY="0.0"/>
                                         <inset key="imageEdgeInsets" minX="43" minY="0.0" maxX="0.0" maxY="0.0"/>
-                                        <state key="normal" title="Scan Code" image="btnCamera--white">
+                                        <state key="normal" title="Scan Code">
                                             <color key="titleColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
                                         </state>
                                         <connections>
                                             <action selector="didTouchUpInsideScanButton:" destination="urv-62-RsD" eventType="touchUpInside" id="YJi-1a-Pg7"/>
                                         </connections>
                                     </button>
+                                    <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" image="btnCamera--white" translatesAutoresizingMaskIntoConstraints="NO" id="bwn-WS-pPa">
+                                        <rect key="frame" x="161" y="207" width="52" height="40"/>
+                                    </imageView>
                                 </subviews>
                                 <gestureRecognizers/>
                                 <constraints>
@@ -273,6 +276,8 @@
                                     <constraint firstItem="RX6-CJ-FV1" firstAttribute="top" secondItem="DV4-GV-ZPf" secondAttribute="bottom" constant="20" id="XN2-Ok-U7y"/>
                                     <constraint firstAttribute="trailing" secondItem="DV4-GV-ZPf" secondAttribute="trailing" constant="16" id="dFu-ak-X2j"/>
                                     <constraint firstAttribute="trailing" secondItem="e7E-iS-3Oc" secondAttribute="trailing" constant="36" id="daW-7v-6MP"/>
+                                    <constraint firstItem="bwn-WS-pPa" firstAttribute="top" secondItem="RX6-CJ-FV1" secondAttribute="top" id="kP9-ti-KFk"/>
+                                    <constraint firstItem="bwn-WS-pPa" firstAttribute="centerX" secondItem="RX6-CJ-FV1" secondAttribute="centerX" id="rzB-mc-mHJ"/>
                                     <constraint firstItem="DV4-GV-ZPf" firstAttribute="leading" secondItem="B4o-Rc-z68" secondAttribute="leading" constant="16" id="sZ7-tO-0jJ"/>
                                 </constraints>
                             </view>