fixed compile error when eigen3 not installed
Cleaning unit tests imports: Removed unneeded #include, i.e. <init.h>
Cleaning unit tests imports: Don't include Labels, when only Math was wanted.
Cleaning unit tests imports: Don't just include what's working.  Include what's needed.
Merge pull request #2008 from sunil1337/compile_error

fixed compile error when eigen3 not installed
Merge pull request #2011 from tklein23/clean_unittest_imports

Clean unittest imports (removed obsolete imports as a first step)
Cleaning imports in class SGRefObject.
Cleaning imports in class init.
Cleaning imports in class SGObject.
Cleaning imports in class MultilabelLabels.
Reformatting Labels to fix indentation before changing.
Cleaning imports in class CLabels.
Cleaning imports in class SGVector.
Adding missing preamble to SGSparseVector.cpp.
Cleaning imports in class SGSparseVector.
Adding missing preamble to BinaryLabels.cpp.
Cleaning imports in class CBinaryLabels.
Formatting BinaryLabels.
Cleaning imports in class CSparseFeatures.
Cleaning imports in class CStreamingSparseFeatures.