corrected the umlauts in "Zürich" (#490)

Author: zber

activity_browser/app/ui/web/startscreen/welcome.html

@@ -71,7 +71,7 @@ <h3>Examples</h3>
 <h2>Development</h2>
 The Activity Browser is an open source project written in Python and
 being developed by a number of researchers in their free time mainly
-from ETH Zürich and
+from ETH Z&uuml;rich and
 University of Leiden (CML). Development&nbsp;is ongoing and new
 features are constantly being added.&nbsp;
 
@@ -88,9 +88,9 @@ <h2>Contributing</h2>
 page on contributing </a>for more detailed instructions.<br>
 
 <h2>Copyright and License</h2>
-Copyright (c) 2017-2019, Bernhard Steubing (Leiden University) and Adrian Haas (ETH Zürich)<br>
+Copyright (c) 2017-2019, Bernhard Steubing (Leiden University) and Adrian Haas (ETH Z&uuml;rich)<br>
 Copyright (c) 2016, Chris Mutel and Paul Scherrer Institut<br>
-Copyright (c) 2015, Bernhard Steubing and ETH Zürich<br>
+Copyright (c) 2015, Bernhard Steubing and ETH Z&uuml;rich<br>
 
 <h2>Copyright and License</h2>
 This program is free software: you can redistribute it and/or