Remove typos

From Elvin:

I attached a patch which drops the validation of the directory name used for caching the prefetched blocks for the TFilePrefetching. I initially used it so that I wouldn't end up with funny names for the cache directory but the Alice guys (cc - Andrei) have some problems with this check when deploying it in production since they have various characters in the directory name which I currently don't accept.

Therefore, I completely removed this validation step and I rely on the TSystem/OS to report any errors if creating/opening the requested directory is not possible.

reshuffling if conditions.

and disable the functionality for not removing template arguments
which are marked to be removed but have a value different from the
default one.
Atlas does not expect this feature and some more coding is involved
since this comparison is not always trivial.

if you have something like A<int, B<double,4, float>> you must
know how many arguments you have to skip for B in advance.

of the users, for example combining a selection xml and a dict selection.

remove trailing blanks

  Regular checks, with a tunable frequency, of process memory were introduce as a first
  debug layer. However, they require calls to System::GetProcInfo which are particurarly
  heavy. Since by default this information is not used, it makes more sense to have it off.

Correct the insertion of the rootmapfile entry in the already seen forward decls. (ROOT-6063 and 6141).

- add only for clang compiler flag -Wno-unused-funciton to suppress the warning