[evlatests] executor simulator

[Walter Brisken]

I wrote a little simulator that you can use to test evla scripts.  It is a 
python program with a stub class library paralleling that in the executor. 
It does no mib commanding and is completely safe to run.  I see two 
purposes for this: 1. test the run-time validity of a jython script, and
2. determine the timing of a script as it runs.  Mostly this is for those 
of us trying to generate jython scripts that do the right thing, but I 
imagine someone else will find a use.  Perhaps operations can use this as 
a file checker?

The program is called ObsSim and it lives (for now) in /home/parallax/bin

Usage:
~~~~~~
/home/parallax/bin/ObsSim <script> <start time> <speedup>

<script> is the Jython file to run

<start time> is the time to reset the clock to prior to running the 
script.  this can be given as:

now	    don't change the time of the clock.  [default]

12:23:12    set to the given LST nearest now

52123.1231  set to given MJD

<speedup> is a parameter that can be used to speed up the runtime so you
don't get bored.  Speedup factors greater than 10 can cause timing 
measurements to become less accurate, but the validity analysis should 
still be OK.

array.modcompWait waits for the user to hit <enter>.

Example:
~~~~~~~~
ObsSim hologtest.evla  0:5:30 2

Starts the simulator at LST 00:05:30 and runs at double speed the file 
"hologtest.evla"


Limitations:
~~~~~~~~~~~~
Cannot use with scripts containing lines such as:
from edu.nrao.evla.observe
These never occur in obs2script generated scripts, but they are in the 
sysstart files.



-Walter