Update Camera Screen texts to reflect that it can also be used for re…

…ceiving btc

The camera screen is usually used for sending bitcoin by scanning a QR code
or pasting an address (or invoice). But it can also be used for receiving
bitcoin by redeeming an Azteco (azte.co) voucher, and soon via lightning with
lnurl-withdraw.

src/components/CameraScreenHeader.js

@@ -42,7 +42,7 @@ export default class CameraScreenHeader extends Component {
     return (
       <View style={styles.header}>
         <StyledText style={[headerStyles.title, styles.title, styles.textShadow]}>
-          Send Bitcoin
+          Send or Receive Bitcoin
         </StyledText>
 
         <ForwardWhiteButton

src/components/QrCodeScanner.js

@@ -234,13 +234,13 @@ export default class QrCodeScanner extends Component {
 
   _renderButton(cameraAuthorized) {
     const { copiedAddress } = this.state;
-    const subtitle = copiedAddress || 'No Address to Paste';
+    const subtitle = copiedAddress || 'Nothing to Paste';
     const disabled = !copiedAddress;
 
     if (cameraAuthorized) {
       return (
         <VibrancyButton
-          label='Paste Address'
+          label='Paste'
           subtitle={subtitle}
           disabled={disabled}
           onPress={this._onPaste.bind(this)}
@@ -265,7 +265,7 @@ export default class QrCodeScanner extends Component {
 
         <ContentView hasToolbar={true} style={styles.content}>
           <Paragraph style={styles.text}>
-            Scan a QR code or paste an address to send bitcoin.
+            Scan a QR code to send or receive bitcoin.
           </Paragraph>
 
           { this._renderViewport(cameraAuthorized) }