Changed histogram so that it is calculated by default using Giovanni's formula for reweighted histogram

[makedocs]

Notice that almost all files were updated with the astyle commit
2813d759

Year in header is here updated to 2017

I replaced
verbatim
endverbatim
with
plumedfile
endplumedfile

in (hopefully) all the places where it was appropriate.

This is a huge commit, applying indentation to the whole
code. Notice that this commit is made on master branch
after having merged with -s ours from branch v2.3

See #215

This is a huge commit, applying indentation to the whole
code.

See #215

    Related to #175

Related to #175

[makedoc]