Add boneanimlib animation part

Adds a part that can play scripted animations on an entity using
boneanimlib. Framedata for animations is downloaded over http. This
commit also comment out a line that prevented normal users from using
the Animation Editor to create animations.
make registeranim() run in a limited sandbox

registeranim() now runs in a limited sandbox environment where it is
only possible to register animations- nothing else is possible. This
commit also cleans up the actual setting and stopping of animations a
bit
Verify "function" is not present in regstring

Just to be safe (we still run registeranim in a sandbox too)
derp

i am so pro
really really important update

don't skip this one folks
a slightly less important update

testing shit
am I cool yet

I am the best lua coder there is hands down
try checking equal to a value instead of nil

it shouldn't ever be -1 anyway
fuck the function check

the sandbox should be good enough
Revert "fuck the function check"

This reverts commit 42fbc620469a0afa65c3c333a5331e86f2a6baba.
Revert "try checking equal to a value instead of nil"

This reverts commit 00b3faaa0a8a87543cd9f2b47ab9c32bb656f5a8.
Revert "am I cool yet"

This reverts commit 37df20ea46b385baeb7709a30a38dcfd4b3a5c91.
Revert "a slightly less important update"

This reverts commit 37ddecd81b56c2bf5d6f88ddc56847b60bb5a6e7.
Revert "really really important update"

This reverts commit 5951bf56f092a61103558e0fe638683393567a99.
Revert "derp"

This reverts commit 5d72558d1f1df713e0413c0c2f3cdd9cebd99d3c.
Revert "Verify "function" is not present in regstring"

This reverts commit da0f6e5066b7eb478212b4c2f2b7eabf1e9fe268.
if the entity is gone, don't set or stop anims

checks to make sure the entity is still valid before making any calls to
boneanimlib
testing webhook

nothing to see here
use JSON balanim format instead of luatable

this makes more sense and is less hacky
Disallow blank anim names, also prefix pac anims

Don't let people make blank anim names (set it to "unnamed" if they
don't put anything), and also prefix balanim part anims with "pac_" for
future use (excluding from animeditor list)