How we can match ANTRL and its runtime version for TL developer.

[TomyYamy]

The problem is

$ apt install antrl

gives us different version of it. It depends on Ubuntu version.
In my case, Ubuntu 18.04 default setting is antrl 4.7 and that conflict with pip install antral-runtime version (now 4.5).
We may think those options.

1. find way of install specific version of antrl.
2. change python runtime side.
   It is very easy. but it will give version conflict with pre-generated parser in rtamt.
3. rtamt setup.py automatically check version of antrl in OS side and install python runtime correctly.

[TomyYamy]

We fixed it for end-user. but high-level user who makes TL from scratch needs more explanation.