Colvars update 2017-03-10

Fix Kokkos issues

Add alloc flag to ev_setup

Add error check to lammps_gather_atoms/lammps_scatter_atoms in library.cpp

Fix spelling "correction" from 3a054d1a: iterations not interactions and imd_writen not imd_written

Small bugfixes

Correct spelling errors in documentation

Kokkos changes

USER-DPD: a variety of small but important bugfixes

Added Kolmogorov-Crespi potential

update AGNI potential for Al, reference runs and output and citation

improve consistency of manual

Fixes for PairAIREBO::bondorderLJ

Uses the sphinxcontrib-spelling extension and requires PyEnchant and
aspell-en to be installed.

Adds the optional make target 'spelling' which produces the file
spelling/output.txt. It contains all words it detects.

Due to the large number of false positives, words in
utils/sphinx-config/false_positives.txt are ignored.