Make main CAN frames list scroll by pixel instead of by item

This small change causes the main window to scroll a lot more smoothly
if you've got a lot of interpreted frames and you've expanded them.
Otherwise scrolling was not a fun time.

ui/mainwindow.ui

@@ -39,6 +39,9 @@
       <property name="alternatingRowColors">
        <bool>true</bool>
       </property>
+      <property name="verticalScrollMode">
+       <enum>QAbstractItemView::ScrollPerPixel</enum>
+      </property>
       <property name="wordWrap">
        <bool>false</bool>
       </property>
@@ -200,7 +203,7 @@
      <x>0</x>
      <y>0</y>
      <width>800</width>
-     <height>19</height>
+     <height>22</height>
     </rect>
    </property>
    <widget class="QMenu" name="menu_RE_Tools">