Fixed build issues using clang and newest GCC versions
Merge branch 'master' of https://github.com/LCSL/GURLS
Fixed bugs and updates.

rmse is now correctly normalized over number of samples;
it is now possible to use splits with size smaller than whole training
set;
hodual now correctly gets median guess instead of mean;
various bug fixes;
Added absolute mean error (abserr) as performance measure
Fixed BuildBoost and BuildHDF5 in external

external boost version is now 1.55, and 64 bit building on windows is
enabled.
external zlib is now working again, and updated to version 1.2.8
Added support for Apple vecLib framework
Added constness to method LtCompare::operator()
Fixed splitho random splitting
Fixed cmake 64bit arch. check
fixed setColumn.
Fixed OpenBlas library search
removed debug print
fixed install target
fixed a bug in siglam.h (it is now possible to use a performance measure under -1).
fixed hogpregr.h, in order to match the recent changes to splitho
updated manuals

added wrappers-tutorial.pdf
added gurlspp.pdf
added bGurls.pdf
added gurlsMatlab.pdf
added bGurlspp.pdf
fixed bug preventing compiling of bgurls++ on some platforms
fixed bgurls++ cmake

when using local HDF5, mpi.h is now included correctly.
Fixes to cmakelists. External builds now have priority over local installations, if selected

Fixes to buildBoost, buildHDF5 and GurlsFindDependecies.
Superbuild is now available on both Linux and Windows.
Openblas 64 bit is now shipped with Gurls++ to permit easier superbuild
on Windows.
Hdf5 is not required  anymore to build gurls++ without bgurls++.
Bug fix in gmat2d.hpp

Size is now correctly set even when gMat isn't owner of the buffer.