Can the owner limit be changed from 10 back to 20?

Was there reasoning for setting the maximum number of owners to 10? I noticed the value was [changed here](https://github.com/christianlundkvist/simple-multisig/commit/18af2c22444cb3b3a62bc5bb9a4d065f5b512a15#diff-bacd3344f07d4093bd385a849cc31e17L13) from 20 to 10 a while back. Consider adding some documentation around that choice.