Dazl

Support for DAML-LF 1.8 DARs.

Make transaction offset parsing compatible with DAML SDK 1.0. Older versions of the DAML SDK are still supported as well.

* Fix pingpong startup instructions.
* Allow for a configurable maximum record time (only takes effect for DAML SDK versions _before_ 1.0).

Fix a bug that caused ready() calls to perpetually hang if a connection was initially opened, but dropped before the ACS could fully be read.

There are minor breaking changes to some usages of `network.aio_run()`; if you do not call this method directly, it should be safe to upgrade; otherwise, there is a minor adjustment that you will need to make to your code:

py
network.aio_run(RunState(RunLevel.RUN_UNTIL_IDLE))


becomes

py
network.aio_run(keep_open=False)

This is primarily a bug fix release.

* Fix a problem in using Numeric types when submitting commands.
* Expose the return value of a choice in exercise events.