#264 rst2html.py: use exit code 1 for errors

[Jendrik Seipp]

I think rst2html.py should exit with an error code different from 0 when an error is encountered.

Example:

$ python setup.py --long-description | rst2html.py > output.html
<stdin>:73: (ERROR/3) Unknown target name: "test".
$ echo $?
0</stdin>

(should be 1)

[Günter Milde]

This is the intended default behaviour. You can change this using
comand line options or configuration settings:

--report=<level>, -r <level>
       Report system messages at or higher than <level>:
       "info" or "1", "warning"/"2" (default), "error"/"3",
       "severe"/"4", "none"/"5"

--halt=<level> Halt execution at system messages at or above <level>.
               Levels as in --report.  Default: 4 (severe).

--exit-status=<level>  
       Enable a non-zero exit status for non-halting system
       messages at or above <level>.  Default: 5 (disabled).