The reason for this change is to eliminate dependencies of
plumedKernel.dylib on plumed.dylib.
Still there is a dependence on plumed_kernel_register that
will be addressed in the next commit.

As suggested by @peastman

Switching function manual was disappeared

Currently, this allows avoiding an exploding number of warnings
originating from amsjit header files to be shown when compiling.

In general, it better decouples asmjit from lepton. Later on
we might allow one to switch asmjit on/off with an environment variable
if desired.

I allowed include commands such as #include "../module/file.h",
only in the case where module is an used module (or the current module).

Later I would like to see if it is possible to eliminate
the "make links" stuff completely.

(still a stylistic warning)

Check first if astyle is present. In this way, when astyle is not compiled,
we get a single error instead of one error per file.

(cppcheck)

Not affecting present usage.

This include dir is used when using not-installed plumed.
Before this fix, using
./configure --prefix=$PWD
was leading to problems related to the overlap between
installed include files and this directory.
After this fix, it will be possible to configure plumed with
./configure --prefix=$PWD

Updated headers for VES

Thanks @hanatok!

Updated lepton to work with the following versions of asmjit:

b7f6d1e369b4b87006851ded9017d3f864ee9d4b
Thu Jan 26 15:55:03 2017
to
673dcefaa048c5f5a2bf8b85daf8f7b9978d018a
Mon Dec 11 02:02:44 2017

Use an example from a more recent asmjit version