Created new cask for Mouse Locator tool. Ordinarily requires manual installation of vendor's app file, but that just installs a preference pane. Tested on OS X 10.11.1 El Capitan.
Note: because of symlinking, preference pane's activate button cannot be toggled! Need to wait for issue #13201 to be resolved to move files instead of symlinking them. Still committing though, in case it works as is on other versions on OS X.