Several small fixes in docs
Added missing tutorial image for path
Merge branch 'v2.1' of github.com:plumed/plumed2 into v2.1
Merge branch 'v2.0-fixes' into v2.0
Fixed mem leak for shortcut vessels
Fixed bugs with undocumented components

Note changes to many regtests are because of changes in labels of
components
Removed regtest analysis/rt43

This test is very sensitive to numerical errors and is thus
not a good test of the code.  The functionality that is
being tested here is tested elsewhere.
Final fix for component registering
Added checks for manual construction

This is for vessels.  Basically you now can't create a FunctionVessel
without adding a description to the manual of the quantity it
calculates
fixed changelog
Fixed mem leak for shortcut vessels

(cherry picked from commit ab117d7971919ecf4b8d1499d9290ba944354a28)

Conflicts:
	src/vesselbase/ActionWithVessel.cpp
Merge branch 'v2.0' into v2.1

Conflicts:
	src/vesselbase/ActionWithVessel.cpp
Secondary Structure: log format
Typo in log of configure
These modules should not be compulsory

plumed core can be compiled without these.

With this change it is necessary to solve a but in the script building the
list of modules to be tested. I took the occasion to simplify it.
Now, all the optional modules are checked, but if a directory is
not present in regtest/ that module is ignored.
Small improvements in configure script

Added possibility to remove checks such as
"-ansi" and "-Wall" (--disable-basic-warnings)

Changed name of temporary files from test... to conftest...
(consistent with autoconf behavior)
fixed char encoding
Merge remote-tracking branch 'origin/v2.1' into v2.1-openmp