message: Changed bitcoins to zcoins in startup message
diff: @@ -149,7 +149,7 @@ QLabel { color: rgb(40,40,40); }</string>
  </font>
  </property>
  <property name="text">
  - <string>Attempting to spend bitcoins that are affected by not-yet-displayed transactions will not be accepted by the network.</string>
  + <string>Attempting to spend zcoins that are affected by not-yet-displayed transactions will not be accepted by the network.</string>
  </property>
  <property name="textFormat">
  <enum>Qt::RichText</enum>
  