Added tag v18.9 for changeset 4de62892e108
Created release v18.9
Fixed spelling errors in comments
setup google analytics
removed piwik stuff
added link to the blog
Moved Google Analytics stuff to the end of the head section.
Renamed unit test program to avoid warnings from cmake
Changed the murmur hash implementation to avoid any possibility of strict
aliasing violations in user code, even when things get inlined in unfavorable
ways.
Made cross_validate_trainer() and cross_validate_trainer_threaded() not make
duplicate copies of the training data since doing so uses a lot of RAM for
large datasets.
updated docs
Added more member functions to the auto_mutex_readonly object that allows
you to convert between a readonly and write lock but still use RAII.
Changed the example to recommend using something like the f1-score when using
BOBYQA for model selection.
Clarified the thread safety of evaluate_detectors().
Renamed assert link check variable to be a little more informative.
updated docs
Moved negate_function() to a different file to avoid an #include ordering bug
that happened when using find_max_single_variable().
updated docs
Added a parameter to control the search radius to the
find_min_single_variable() and find_max_single_variable() routines.  Also made
these functions a little more robust to unusual objective functions.
Fixed a bug, the initial step size wasn't being used in part of the
code.  Also made the initial bracketing step a little more efficient.