Peter M. Groen / openbr

Surely this will save many bytes of source code.

…rom ground truth bounding boxes.

Only verification mode evaluation is supported. The main issue is to avoid
loading potentially very large similarity and mask matrices into main
memory.

Defaulting to ClusterID did not make much sense, since the key being indexed is
in fact the ground truth, not the cluster labels (cluster labels are stored as
indices in a csv file, not a gallery).

Also, use Format to read similarity matrices instead of assuming mtx is in use.

Instead of returning references to static memory (which are invalidated by
subsequent or concurrent calls to the function), require users to input string
buffers to functions that return strings.

Affected functions:
br_get_filename
br_get_metadata_string
br_scratch_path
br_objects
br_most_recent_message

In some GUI functions, use C++ functions instead of going through the c api
add a c++ method correspondign to br_objects (which returns a stringlist
instead of merging the lines)

br_read_pipe and br_get_header also use static memory in a similar way, but
are not addressed in this commit.

…-gui is specified as the first argument

The primary addition is ProcessWrapperTransform, which takes a transform as a
child, and creates a worker process that runs that transform. The main point of
this is to handle cases where we interface with non-threadsafe code, and need
to isolate transforms in their own processes if we want to use multiple copies
of them.

Inter-process communication is handled using QLocalServer/QLocalSocket, the
actual worker processes are additional instance of br, which does mean this
bleeds out to the public API to an unfortunate extent.

Initial trvial tests seem promising, but generally we can expect performance
to degrade if larger amounts of data are transfered, ideally we should do
ProcessWrapper(Open+FeatureExtraction), so the data transfered to the worker
is an image name, and the data transfered from the worker is a feature vector.

Resolved conflicts:
	app/br/br.cpp
	openbr/core/bee.cpp
	openbr/plugins/output.cpp

resolved conflicts:
	app/br/br.cpp
	openbr/core/bee.cpp
	openbr/core/classify.cpp
	openbr/core/cluster.cpp
	openbr/core/eval.h
	openbr/openbr.cpp
	openbr/openbr.h
	openbr/plugins/algorithms.cpp
	openbr/plugins/independent.cpp
	openbr/plugins/output.cpp
	openbr/plugins/svm.cpp

If just the first property name argument is specified, use that for both the
gt and predicted files.

Use empty strings to indicate when the gt/predicted property names are not
supplied to facilitate the above change.

Fix argument count checks for eval regression/classification.

Change default label name from Subjet to Label (since label is a more general
term).
Use different default variable names for classification (label), regression
(regressor/regressand), and clustering (ClusterID)
Update some (far from all) transforms to accept arguments specifying their
input/output variables.
Update eval classification to optionally take target variable names as
arguments