cantera: migrate from Homebrew core

Closes #948.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
gromacs: migrate from Homebrew core

Closes #947.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
sundials: migrate from Homebrew core

Closes #946.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
gromacs 4.6.5

Perform build-time tests.

Closes #959.
nfft 3.2.3: new Formula

Closes #396.
plink: Patch to fix build, add test

Closes #958.
hypre 2.9.0b

Hypre is a library of high performance preconditioners that features
parallel multigrid methods for both structured and unstructured grid
problems.

Closes #906.
megam 0.9.2: Maximum entropy machine learning package

megam and megam.opt (the optimized version) are machine learning commandline tools
used by Python NLP Toolkit (nltk) if the built in libraries are too slow.

Closes #949.
Use File.exist? instead of File.exists?

File.exists? is deprecated in Ruby 2.1+.
ASL: option to build Matlab interface.