Make several crimes against the clear commands

[NoComment1105]

Fixes #346

This all works pretty much first try so it's voodoo code i will never ever look at again. Please review! :D

[tempest15]

I'm confused about what the message count argument does on the clear between command. Seems like it just does the latest, so seems redundant with clear before/after.

We might want some sort of maximum because I did successfully delete 100 messages but it took a while.

What does clear before without a count argument do? Seems dangerous. Just generally, I think it might be good to have some sort of safety mechanism to cancel the process, no clue if that's at all possible.

You do need to clear up conflicts, but functionality looks good, sorry for taking so long to get to it.

[NoComment1105]

Yeah looks like that count argument was redundant in the between command.

The maximum discord allows is 100. I can reduce it if you feel it necessary.

All commands have a maximum delete count of 100 as that's the discord limit, so there should be no issue if before is used and no count argument specified

[tempest15]

Looks good