MDSReader test refactoring. Bug retated with time double precision and...

MDSReader test refactoring. Bug retated with time double precision and segments corrected. Bug in which Synchronise() return false (end of data) in the last iteration corrected. Now the Datasource only returns end of data when is not reading data, if reads 1 sample over many is still returning true (not end of data). Tests added catching float precision problems and tests modified to test that last segment is read.