remove beacon cursors when beacon mode is disabled

Solves #290. Now when beacon mode is disabled, we call
meow--beacon-remove-overlays do disable the fake cursor overlays.
Note the secondary selection remains active. When beacon mode is
resumed, the cursors are preserved. Because all states are disabled
from meow--disable, this solves the case where meow-mode is called
directly.

Author: eshrh

meow-core.el

@@ -90,7 +90,8 @@
         (meow--cancel-selection)
         (hl-line-mode -1))
     (when meow--beacon-backup-hl-line
-      (hl-line-mode 1))))
+      (hl-line-mode 1))
+    (meow--beacon-remove-overlays)))
 
 ;;;###autoload
 (define-minor-mode meow-mode