[FIX][DOC] (libstfinv): apply correction to README.status

the fixed wavelet engine ist not yet implemented

src/libs/libstfinv/README.status

@@ -9,10 +9,8 @@ Both, C++ and C API are implemented and operational.
 
 Currently available engines:
     ident: identity: just apply a scalar factor
-      fix: use fixed wavelet as read from file
     fdlsq: least squares in the frequency domain
 
-
 Fourier domain least squares engine (fdlsq)
 -------------------------------------------
 class       stfinv::STFEngineFDLeastSquares