Allow suppressing or overriding halo rendering

[Python1320]

May be used to reimplement halos without having to override the library or for situations where halos may be clashing with aesthetics or rendering (better to hide halos temporarily than have them glow through areas or force people to hook the halo library).

[Kefta]

Add parentheses around the if condition.

[storm37000]

List will memory leak really badly if you stop the hook at that position. Halos would still be added with Add function but not cleared from the list.

You can override the Add function to effectively stop halos.

[garryspins]

Should probably use a new hook, CanDrawHalo(entry) for verbosity and backwards compatibility sake as some random addon might return false making issues hard to diagnose in the event of this being merged.