Allow flashing of images via the GUI

- Use the Images... button in the lower right of the zip install
  page
- Unify image flashing functions between restore and image flash
- boot and recovery partitions are flashable by default
- use fstab flag flashimg=1 or 0 to override defaults
- file system partitions are currently not flashable

Change-Id: I822dc446030543c55d2153e219d67a1292374ffc
diff --git a/gui/devices/280x280/res/ui.xml b/gui/devices/280x280/res/ui.xml
index 971e637..ae8c27d 100644
--- a/gui/devices/280x280/res/ui.xml
+++ b/gui/devices/280x280/res/ui.xml
@@ -74,6 +74,7 @@
 		<variable name="row11_text_y" value="209" />
 		<variable name="row12_text_y" value="228" />
 		<variable name="row13_text_y" value="237" />
+		<variable name="flash_list_height" value="140" />
 		<variable name="zip_status_y" value="265" />
 		<variable name="backup_text_y" value="50" />
 		<variable name="col_progressbar_x" value="31" />