Added regtest on DRMSD

I suspect a problem in v2.1 with DRMSD cutoff.

This test is working properly in v2.0
Merge branch 'v2.0' into v2.1

This highlights bug #123
Seems to fix #123

@gtribello please check before I merge!
[makedoc]
tutorials: fixes
Fixed typos in spelling of UPPER_CUTOFF
Merge branch 'v2.1-fix-123' into v2.1

[makedoc]

closes #123
plumed patch check also for Plumed.cmake.* files

close #124
changelog

[makedoc]
Merge branch 'v2.1'

[makedoc]