Not used now, but might be used in the future to better
translate exceptions.

When using the C++ interface, this change remaps exception within plumed
to a class that inherits from std::runtime_error.
This allows them to be catched also from an MD code linked to
a different C++ library.

I also removed some cpp options, I think it is better to enforce
exceptions to be managed in this way.

Returned argument should be last.

* flying Gaussian added

* Update MetaD.cpp

Making plumedcheck happy

* Update MetaD.cpp

Making plumedcheck happy again

* Update MetaD.cpp

Making plumedcheck finally happy

* regtest for flying Gaussian

* Update MetaD.cpp

Adding flying Gaussian with parallel tempering.

* Update MetaD.cpp

* Flying Gaussian with Parallel tempering

* Added PT to FG

* PT for FG

* PT for FG

* PT for FG

* pokus

* Making patch to know from plumed.dat

* Make patch know from plumed.dat

* Make patch know from plumed.dat

* Make patch to know from plumed.dat

* Update GREX.cpp

* Update GREX.cpp

* Update PlumedMain.h

* Update GREX.cpp

* Update GREX.cpp

* Update GREX.cpp

* Update repl_ex.cpp

* PTFG

* oprava

* blbost

* blbost2

* flying gaussian with parallel tempering

* PTFG

* just Flying Gaussian without PT

* just Flying Gaussian without PT 2

- expand some macros
- order methods

New Plumed.h file, with more features (see #385)

Closes #354

Should be more robust when combining different libraries.

- Added macros to simplify addition of new functions
- Added all trigonometric functions that were present in libmatheval
- Added atan2

- Added many points to rt-lepton test
- Added nandelta() function
- Made definitions of delta(0) and step(0) equal to matheval

Works both with and without ASMJIT

Makes it easier to compare regtets on different machines.

fixed a few typos

Atomic units