Merge branch 'v2.1'

.travis.install.almost

.travis.yml

regtest/basic/rt65-mpi/COLVAR.0.reference

regtest/basic/rt65-mpi/COLVAR.1.reference

regtest/basic/rt65-mpi/Makefile

regtest/basic/rt65-mpi/ala12_trajectory.xyz.0

regtest/basic/rt65-mpi/ala12_trajectory.xyz.1

regtest/basic/rt65-mpi/config

regtest/basic/rt65-mpi/plumed.dat

regtest/has-almost/rt0/derivatives1.reference

regtest/has-almost/rt0/plumed.dat

regtest/has-almost/rt2/Makefile

regtest/has-almost/rt2/ala12_trajectory.xyz

regtest/has-almost/rt2/colvar.reference

regtest/has-almost/rt2/config

regtest/has-almost/rt2/plumed.dat

src/colvar/NOE.cpp

src/colvar/RDC.cpp