add first part for DataSetViews.
DataSetView(DataSet& dataset) is changed to an empty subview
of the dataset.
Add DataSetView helper method implementation for cross validation:
 * OpenANN::split(group, dataset, number_of_groups)
 * OpenANN::split(group, dataset, ratio)
 * OpenANN::merge(destination, group)
Add TestCases for DirectStorageDataSets and DataSetViews.
Add DataSetTestCase to the main runner in test/test.cpp.
The more complex SplitableDataSet can be directly replaced by the simple
DataSetView implementation.
add a flag for shuffling the main dataset before splitted to different
subviews.
Add doxygen documentation for DataSetViews.
Fix test cases in debug build.
wrap header documentation in OpenANN/io/DataSetView.h after 80 letters.
reserve memoryspace in std::vector where the size is known
in OpenANN::DataSetView.
use strict CamelCase convention for method names in DataSetTestCase.
Merge branch 'datasets' of https://github.com/Ruun/OpenANN into Ruun-datasets
Merge branch 'libsvm' of https://github.com/Ruun/OpenANN into Ruun-libsvm

Conflicts:
	test/test.cpp
update