Merge branch 'hydro_dev' of https://github.com/ptrb/ipa_loc_feature_slam into HEAD

Conflicts:
	src/ipa_loc_feature_slam_ros.cpp
	src/slam_data_uz.cpp
	src/slam_landmark.cpp
	src/slam_landmark.h
	src/slam_observation.cpp
	src/slam_particle.cpp
	src/slam_particle.h
	src/slam_processor.cpp
remove merge errors
found and killed "wrong-subtree"-Bug
refactored slam_landmark
deleted Bug "measureLikelihood == NaN in quadTrees"
re-added ellipse search in findSimilatFeatures (is not perfect...)
more bugsearching and -fixing (and producing...)
working (?) version of quad_tree, still slow
remove v_landmark-implementation
Error removed: "exact not found"
quad-merging works. Program runs!
direct neighbourhood link
made it a bit faster
switched from recursion to loops -> great speed boost!
implemented multi-parent-ability
corrected a wrong merge
small changes
Merge branch 'quad_tree' of github.com:jsabsch/ipa_loc_feature_slam into quad_tree

Conflicts:
	src/ipa_loc_feature_slam_ros.cpp
	src/slam_landmark.cpp
	src/slam_landmark.h
	src/slam_observation.cpp
	src/slam_particle.cpp
	src/slam_particle.h
	src/slam_processor.cpp