Changeset 916 for trunk/yat/statistics/pearson_vector_distance.h

Sorry this commit is a bit to big.

Adding a yat_assert. The yat assert are turned on by providing a
'-DYAT_DEBUG' flag to preprocessor if normal cassert is turned
on. This flag is activated for developers running configure with
--enable-debug. The motivation is that we can use these yat_asserts in
header files and the yat_asserts will be invisible to the normal user
also if he uses C-asserts.

added output operator in DataLookup2D and removed output operator in
MatrixLookup?

Removed template function add_values in Averager and weighted version

Added function to AveragerWeighted? taking iterator to four ranges.