If there's already a `LockOn` instance, clear its lock before creating creating a new one. Fixes a shaky viewport effect after certain transitions.
Includes:
* Slight refactor (elementId wasn't an id, but a selector - it included the "#" prefix)
* Add support for a[name=X] anchors in `jumpToPost`
* Scope down anchors to the #main element (Embeded fontawesome sprites are causing conflicts, e.g. when given `bed` anchor, `<a name="bed">` was at odds with `<symbol id="bed" viewBox="0 0 640 512">(…)</symbol>`)
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