added support for leave-one-out cross-validation.
fixed a bug in the Conditional model generation...

Now, the conditioning information is also saved in the modelInfo
Fixed a bug in the ConditionalModelBuilder.h
Merge pull request #2 from rblanc/development

Development
updated documentation to better explain the difference between Dataset, Sample, SampleVector and SampleData
Renamed SampleData into SampleDataStructure, and updated the documentation
Merge remote-tracking branch 'rblanc/development' into development
Changed SampleData into SampleDataStructure in unit tests
Merge remote-tracking branch 'upstream/development' into development