NOE and RDC: parallelised
ensemble
ensemble: fix of the fix
Added benthic toleration
Added new method for constructing functions of multicolvars

Also fixed bug in KernelFunctions
Added version number to manual "Home" button

Fixes #70
Readded a few tabs

I added a few tabs to the html manual:
Getting Started
Tutorials
Index of Actions
Added note on #115
Merge branch 'v2.0' into v2.1
Fixes to benthic erosion, minor performance improvement for TTMetaD.
Merge branch 'fix-70' into v2.1
Backport of fix-70
Merge branch 'v2.0' into v2.1

I had to remove the postproc.sh file added in v2.0
to post-process html files (in v2.1 this is done in go-doxygen)

Conflicts:
	user-doc/Makefile
Merge branch 'v2.1'
Fixed error in doc
Added doc
Merge branch 'v2.0' into v2.1
Merge branch 'v2.1'
Implemented UPDATE_FROM and UPDATE_UNTIL

When specified, the update() method is only invoked
within this time range. This allows to perform some tasks
in a single simulation, e.g.:
Equilibration + Metadynamics + umbrella sampling refinement
with analysis of the last part only.

Currently this is an optional flag for all the actions.
I am not sure this is a good idea (currently update() method
is only used in some ActionPilot), since this will make
the keyword appear in every manual page.
However, since the update method is in principle available on all
the actions I preferred to add these keywords everywhere.

Fixes #65
Added regtest for UPDATE_FROM and UPDATE_UNTIL