wait keyword and process

[Adrodoc]

Add a keyword wait that will wait for one tick.
To wait 2 or more ticks there should be a process with the name wait with a parameter time of type value as defined in #31.
This process should have the modifier remote (#34) to make sure that calling and returning takes one tick each.

An implementation could look roughly like this:

remote repeat process wait(value ticks) {
  ticks -= 1
  if: ticks < 2
  then {
    return
  }
}

[Adrodoc]

Instead of a wait keyword we could use an inline process with an embedded script via #43. The script would then check the ticks parameter to decide whether to delegate to a remote implementation or use a local 1 tick delay:

process wait(Integer ticks) {
  groovy {
    if (ticks <= 1) {
      mpl << 'start ${this + 1}'
      mpl << 'skip'
    } else {
      mpl << "waitForValue(${ticks})"
    }
  }
}
repeat process waitForValue (Value ticks) {
  ...
}

[Adrodoc]

If the first implementation is chosen (wait keyword) it might be possible to remove the keyword skip and relative this inserts /say ${this + 1}, because they are only really useful for waiting one tick. This would simplify a lot of code, because we could get rid of the internal/generated by flag. Maybe relative this inserts should be kept for debugging purpuses, in which case they could just operate in chainlink basis rather than on chainpart basis.