Added back Laser Frame to URDF

This in an effort to fix issues.  It should be redundant and
unnecessary.  The depthtolaserscan node should also be publishing the
camera -> laser transform.  They should be the same, but to avoid
contention I had removed the laser frame from the URDF.  Apparently
the depthtolaserscan node may not be broadcasting, so added back in to
make sure someone is.

bot_description/urdf/bot_front_caster.urdf

@@ -90,4 +90,14 @@
 
   <link name="camera_link"/>
 
+  <!-- Laser scanner (placed at camera but horizontal) -->
+  <!-- Careful: the angle must match the 17deg above!  -->
+  <joint name="cameratolaser" type="fixed">
+    <parent link="camera_link"/>
+    <child  link="laser"/>
+    <origin xyz="0 0 0" rpy="0 0.297 0"/>
+  </joint>
+
+  <link name="laser"/>
+
 </robot>

bot_description/urdf/bot_front_wheels.urdf

@@ -90,4 +90,14 @@
 
   <link name="camera_link"/>
 
+  <!-- Laser scanner (placed at camera but horizontal) -->
+  <!-- Careful: the angle must match the 17deg above!  -->
+  <joint name="cameratolaser" type="fixed">
+    <parent link="camera_link"/>
+    <child  link="laser"/>
+    <origin xyz="0 0 0" rpy="0 0.297 0"/>
+  </joint>
+
+  <link name="laser"/>
+
 </robot>