Update README.rst

Fixed documentation to mention restriction on MCNP materials formatting for mats2ALARA. 
Adding an initial set of tests for mcnp_n2p.py for dagmc inputs. See also #16.
Merge branch 'master' of https://github.com/svalinn/r2s-act
Moved test for scdmesh_convert to scripts/legacy/.
temporary fix to r2s_step1.py it make it compatible with read_meshtal.py. read_meshtal.py will needs some refactoring
Test file path corrections for robustness.
Merge branch 'master' of https://github.com/svalinn/r2s-act
Testing of handling of multi-line cards and indents.
fmesh option in r2s_step2; mcnp_n2p handles dagmc

fmesh card option added to r2s_setup (aka r2s.cfg)... previously such an
addition would require replacing all currently used r2s.cfg files.

To get around this limitation, how r2s_step2.py handles parameters was
redone so that ``try:`` can be used in checking each parameter.

mcnp_n2p now handles identifying whether an input is a dagmc or a mcnp
input.
Fixed error that slipped into a test.
fixes, file/path format, full urls
More efficient sampling (re-uses a random number, as per Vose (1991).
More flexible condition
MCNP source readme updates.
Update location of CAE custom MCNP executable.
fixed bug in handling of single energy meshtals with no energy column
New alias table algorithm implemented. Passes tests, and CAE executable updated.
Merge branch 'master' of https://github.com/svalinn/r2s-act
Missing word
Fixing logic error (the .. or .. and ..), and cleanup.