Update README.md

README.md

@@ -16,6 +16,7 @@ Besides standard python libraries, the project builds on the following libraries
 * matplotlib
 * docutils
 * pyQt4
+
 Optional:
 * xlwt and / or XlsxWriter for exporting filter coefficients as *.xls(x) files
 
@@ -42,6 +43,8 @@ or files from pyFDA using e.g.
 
 ### Customization
 
+The layout and some default paths can be customized using the file `pyfda/pyfda_rc.py`.
+
 ### Why yet another filter design tool?
 * **Education:** There is a very limited choice of user-friendly, license-free tools available to teach the influence of different filter design methods and specifications on time and frequency behaviour. It should be possible to run the tool without severe limitations also with the limited resolution of a beamer.
 * **Show-off:** Demonstrate that Python is a potent tool for digital signal processing applications as well. The interfaces for textual filter design routines are a nightmare: linear vs. logarithmic specs, frequencies normalized w.r.t. to sampling or Nyquist frequency, -3 dB vs. -6 dB vs. band-edge frequencies ... (This is due to the different backgrounds and the history of filter design algorithms and not Python-specific.)