Basically just lets you provide any formspec you want, which should resolve all of the "but the touchscreen can't do XYZ" issues :)
I don't believe this to be a security problem as arbitrary formspecs should do nothing unless you actually right-click the node (and you can always just... not), and if the client does crash in response to a bad formspec then this is probably a client bug anyway.
* add luacheck workflow and config
* replace 'digiline' with 'digilines'
* fix whitespace
* fix most variable warnings
* piston.lua and movestone.lua have inline ignores for some hard to fix code
* increase line length for now
