added constructors for LogDetEstimator
added tree structures for id3
added constructors LogDetEstimator,unit tests for those and added get methods for private variables of LogDetEstimator
BinaryTreeMachineNode created
fixed typos in #1940
added docs to #1940, unneccesary data from unit tests
unit-tests added for valgrind check
unittest names changed
removed constructor for dense matrix
REQUIRE condition removed to counter travis failure
Merge pull request #1950 from mazumdarparijat/pca

added data structures for decision tree implementation
CMake-ize documentum generation
Doxygen documentation was waaay out of date and it was still using the
old make system. updated:
 * documentation is generated via cmake i.e. `make doc`
 * outdated doxygen descriptions are removed
 * since doxygen 1.8.0 markdown is supported, i have added some of the markdown documentation to doxygen
 * changed some of the markdown documentations' style to standard markdown from GFM since only standard
  markdown is supported by doxygen
 * fixed some minor errors in the documentation
fix failing input error in logdet notebook
Merge pull request #1968 from lambday/develop

fix failing input error in logdet notebook
Merge pull request #1940 from sunil1337/develop

added constructors for LogDetEstimator
remove german umlaut
Issue #1955; change loglevel through environment variable
fixes #1955; added a function init_from_env