The problem was that some arrays had predefined sizes that were
not adapted to the actual problem. I changed this for some arrays
now but there are still some other arrays that may become a problem
at some point, too.

The problem was that in certain situations the origin was identified
as a corner point of the IBZ while it actually was not. It is not a
corner point if less than 3 faces of the IBZ feature this point.

The threshold was used at several places to decide whether two values
are identical, on which side of a plane a point lies, and so on. The
strict value before lead to problems as some points were not considered
to be identical due to numerical reasons, although they were meant to
be identical. The larger threshold now solves the problems.

However, if more problems like this arise it should be checked whether
the threshold has to have different values at different places in the
code. Also additional code may be required to treat certain cases in
a special way.

nbsz determines the size of the region in reciprocal space considered
to construct the IBZ. Up to now this variable was set to 3 in julia.f.
But this value is not necessarily save. We now calculate a save but
also conservative value for this now local valiable nbszLocal in
brzone2.f90.

Also in this commit: Added build.* to .gitignore.

This commit and the 2 before made init/brzone2.f90 faster by
introducing or tightening constraints to filter out possible
boundary planes of the IBZ at an early stage of the algorithm.

I hope I didn't go too far.

Since the routine brzone featured many bugs that occured in special
cases I now reprogrammed the functionality of the routine in the
new subroutine brzone2. The new algorithm is simpler and should
be less vulnerable to the mentioned special cases. It also is slightly
slower. The new routine takes about 2 seconds.

By commenting the new routine out and the old one in both algorithms
can directly be interchanged.