libtsxx, libdatrwxx [MERGE]: merge fix_sigfit into master
When compiling sigfit, the overloaded function resolution algorithm selected the wrong output operator for ts::TimSeries objects. An output operator for writing instances of this object type to datrw::oanystream was missing. For this reason the overloaded output operator for aff::Series type objects to datrw::oanystream was selected by casting ts::TimeSeries to its public base class type aff::Series. Solved the problem by providing additional output and input operators in libtsxx and access to the debug flag in ianystream and oanystream in libdatrwxx.