Small fixes to the ROI distances and angles example (#521)

* remove redundant label parameter form .plot method call

* flip (counter-)clockwise

Author: niksirbi

examples/boundary_angles.py

@@ -144,15 +144,9 @@
 # Overlay an image of the experimental arena
 arena_ax.imshow(plt.imread(arena_image))
 
-central_region.plot(
-    arena_ax, facecolor="lightblue", alpha=0.25, label=central_region.name
-)
-nest_region.plot(
-    arena_ax, facecolor="green", alpha=0.25, label=nest_region.name
-)
-ring_region.plot(
-    arena_ax, facecolor="blue", alpha=0.25, label=ring_region.name
-)
+central_region.plot(arena_ax, facecolor="lightblue", alpha=0.25)
+nest_region.plot(arena_ax, facecolor="green", alpha=0.25)
+ring_region.plot(arena_ax, facecolor="blue", alpha=0.25)
 
 # Plot trajectories of the individuals
 mouse_names_and_colours = list(
@@ -422,11 +416,11 @@
 # Egocentric angles, on the other hand, fluctuate more due to their sensitivity
 # to changes in the forward vector. Outside frames 200-400, we see trends:
 #
-# - ``AEON3B_TP2`` moves clockwise around the ring, so its egocentric
+# - ``AEON3B_TP2`` moves counter-clockwise around the ring, so its egocentric
 #   angle decreases ever so slightly with time - almost hitting an angle of 0
 #   degrees as it moves along the direction of closest approach after passing
 #   the other individuals.
-# - The other two individuals move counter-clockwise, so their angles show a
+# - The other two individuals move clockwise, so their angles show a
 #   gradual increase with time. Because the two individuals occasionally get in
 #   each others' way, we see frequent "spikes" in their egocentric angles as
 #   their forward vectors rapidly change.