Linking parameters fixed and proper "Show all" button

The "others" and "timerange" parameters described on the Linking page should now work again. They were broken since the anchor navigation upgrade. Thanks to Oba JA7UDE for the bug report!

To properly fix how the "others" parameter  works I also added a new "Show all" button which is now quite a bit more  sensible than the old "Show all" link:

• The button is disabled and greyed out when it really doesn't do anything (like, when you're not tracking a station and all stations are displayed anyway)
• "Show all" can now be toggled between on and off, not just on
• The button visually indicates whether it's on or off (depressed or not)