change Window title to "Bitcoin - Wallet" / misc related renames

- this helps user to not think our Client is called "Bitcoin Wallet"
- change "About Bitcoin-Qt" to "About Bitcoin"
- change "Bitcoin debug window" to "Bitcoin - Debug window"
- change "Client" in debug Window to "Bitcoin Core"

src/qt/forms/rpcconsole.ui

@@ -11,7 +11,7 @@
    </rect>
   </property>
   <property name="windowTitle">
-   <string>Bitcoin debug window</string>
+   <string>Bitcoin - Debug window</string>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout_2">
    <item>
@@ -36,7 +36,7 @@
           </font>
          </property>
          <property name="text">
-          <string>Client</string>
+          <string>Bitcoin Core</string>
          </property>
         </widget>
        </item>