Add conserved quantity for Berendsen P-couple
The work the Berendsen barostat applies on the system is calculated
and integrated. This work is stored in a new entry in t_state.
Note that this makes it impossible to checkpoint continue or
concatenate energy files from older runs with Berendsen P-coupling.
Added formula for conserved quantity to the manual.
Now nearly all coupling algorithms support the conserved energy
quantity, added a paragraph on this in the manual.
Change-Id: I357fcd9edaba957a11bb02e39c746abfff37189e
13 files changed: