Added keyword 'repeat' to test specification

This small change allows tests to be run multiple times without
having to manually create extra tests. It is invoked by adding the
'repeat' value in the 'rtest' declaration of the rxml (it is not required):

...
<rtest name="elastic-random" repeat="10">
...

This will create copies of the tests (in the testresults dir) named

elastic-random_01
elastic-random_02
...
elastic-random_10

and will be run and reported on as individual tests. This will easily allow
random tests to greatly increase the test coverage (and leverage the speed
and small storage footprint of GMD).
Merge branch 'master' of https://github.com/tjfulle/gmd
update to exodus writer tpl
better diagnositics of bad input to eos driver
bug fix in response function evaluater
Adding -B switch to gmd to make materials before running
Fixed up args sent to material model
Update to docs
Merge branch 'master' of https://github.com/tjfulle/gmd
Actually implementing the repeat option correctly

Sorry about so many commits. I know that it isn't very
professional to not squash them - but I got some updates
from you since then, so I don't want to try to squash them.
update to eos driver and bug fixes to surface extraction.  hugoniot extraction still does not look right
Merge branch 'master' of github.com:tjfulle/gmd
Merge branch 'master' into topics/viz
Update to way random numbers are generated.

The random state is set with the default (system time) seed, unless
explicitly set by the input file.  Set the random seed for preprocessing
with the random_seed keyword.