Fastcluster

• Updated the "members" specification in the User's manual to reflect the
recent change.

• Release the GIL in the Python package, so that it can be used efficiently
in multithreaded applications.

• Improved performance for the "Ward" method with vector input.

• The "members" parameter in the R interface is now treated as a double
array, not an integer array as before. This was a slight incompatibility
with the stats::hclust function. Thanks to Matthias Studer, University of
Geneva, for pointing this out.

• Replaced ptrdiff_t by std::ptrdiff_t, as GCC 4.6.1 complains about this.

• Fix for Solaris: replaced ssize_t by ptrdiff_t in the C++ code.

• Removed the NN-chain algorithm for vector input: it was not clear that
it would work under all circumstances with the intricacies of floating-
point arithmetic. Especially the effects of the excess precision on the
x87 are impossible to control in a portable way. Now, the memory-saving
routines for the “Ward” linkage use the generic algorithm, as “centroid”
and “median” linkage do.

• Fixed test scripts, which indicated an error on some architectures, even
if results were correct. (The assumption was that ties in single linkage
clustering are resolved in the same way, both for dissimilarity input and
for vector input. This is not necessarily true if the floating point unit
uses "excess precision". Now the test scripts are content with arbitrary
resolution of ties and do not assume a specific scheme.)

• Bug fix: uninitialized function pointer in Version 1.1.0

• Routines for clustering vector data.

• Added a User's manual

• Revision of all files