Fix Amber mdcrd parser so it does not rely on whitespace-delimited coordinate
fields. The Amber mdcrd file prints out 10 numbers per line in the format %8.3f.
If a number takes up 8 spaces (i.e., -100.000 <= X <= 1000.000), there will be
no space between that number and the next.  Since the units are Angstroms, this
is equivalent to saying no atom can move more than 10 nm over the course of the
simulation.  These mdcrd files are quite common.
Merge remote-tracking branch 'origin/master' into fixmdcrd
Add a test case for an Amber mdcrd file.  This is a contrived example taken from
the Amber test suite in which one coordinate was modified to fill all 8 spaces.
Since I never use mdcrd files myself (NetCDF only), and I usually enable
wrapping, I didn't have an example on-hand.
Add atomic numbers to the prmtop to make this a more extensive test.
Merge pull request #431 from swails/fixmdcrd

Fix Amber mdcrd parser