TODO

Just a list of tasks to do without order

* Porting to 64 bit platforms
kkk

* Image masking
Pass a mask image created elsewhere (pre-processing) and evaluate the classifier
only on some places.
    
* Non-maxima suppression
Grouping of results to remove multiple detection. Maybe make function like:
int group_detections(results, n, threshold);

* Return largest object (stop at first detection on smallest scale)
In some applications only a largest object is searched for and it can save
many computations to search only on small scales of pyramid.

* Window prunning (through masking)
Use a mask created by edge detector which rules out flat areas.

* Multicore support (OMP?)
When available, more cores can be used. The speed-up is nearly linear.

* Neighborhood suppression
A simple extension which can rule out image positions which are not likely to
contain a target object. This extection is based on machine learning which
re-uses calulated features to predict response on neighboring positions.
** Update classifier structure to hold suppression alphas
** image scanner which can update mask from results of weak hypothesis
** WH that supports suppression alphas

* ARM Neon support?