An efficient version for usage

In this release, we deliver 3 features could greatly increase the using experiments.

1) Meta file: support macro, support combined format

In the previous version, when we want to do a job in the meta file(the script) like: prepare : conf-1 : run : conf-2 : run.
It's OK when the step run don't have args.
But when run is a tiny flow (like, 2~3 commands) and sometimes having args, we need to provide a "wrapper" command(and another script file) for run.

The feature macro and combined meta provide an easier way to meet these needs.

Macro example:

help = this is a demo `.ticat` or `.tiflow` meta file

# define a macro `run`
[[run]] = step-1 : step-2

# use macro `run`
flow = prepare : conf-1 : [[run]] : conf-2 [[run]]

Combined meta file example:

### file: app.display.utf8.off.tiflow
help = not use utf8 display by default
flow = display.utf8.off : env.save

### file: app.display.utf8.symbol.off.tiflow
help = not use utf8 symbol display by default
flow = display.utf8.sym.off : env.save

2) Env snapshot toolbox

This version has commands env.snapshot.save <name> and env.snapshot.load <name>, it could prevent the default env become a mess.
For example, we could save env to a named-snapshot after prepare, then load the snapshot before run.

3) Break point command break.here

It's convenient, some examples:

• Instead of break.at.begin, stop at the beginning: ticat break.here : my-job, then we could do a step-by-step dry-run, or skip some commands in the job.
• Instead of break.at.end: ticat sessions.last.retry : break.here, then enter interact-mode, check and save env from an executed job to a snapshot.

To sum up, this version is handy and efficient, enjoy!

Update to this version by:

ticat update.self