fix Qt link

This is just to fix the link that now sends to a German one...

The doc would still need to be updated with more recent systems (and potentially only with Qt5)

README

@@ -26,9 +26,9 @@ sudo apt-get build-dep vite
 -------------------------------
 Otherwise (Debian/Ubuntu users):
 
-If you do not have Qt please visit : http://www.qtsoftware.com/downloads/opensource/appdev and download the development files for your operating system.
+If you do not have Qt please visit: https://www.qt.io/ and download the development files for your operating system.
 
-you can use apt-get :
+you can use apt-get:
 sudo apt-get install vite
 
 For Debian users, you may need to install several packages:
@@ -65,12 +65,12 @@ rpm -i qt45-4.5.1-1.el5.pp.i386.rpm
 rpm -i qt45-sqlite-4.5.1-1.el5.pp.i386.rpm
 rpm -i qt45-devel-4.5.1-1.el5.pp.i386.rpm
 
-You have to export your PATH variable to the directory of qmake, which is by default :
+You have to export your PATH variable to the directory of qmake, which is by default:
 export PATH=/usr/lib/qt45/qt/bin:/usr/lib/qt45/qt/include:$PATH
 
-If it is not the case, try : find / | grep qmake and take the path given.
+If it is not the case, try: find / | grep qmake and take the path given.
 
-Go to the vite/src/trunk directory then :
+Go to the vite/src/trunk directory then:
 ./configure
 make or gmake will create the binary file.
 
@@ -84,19 +84,19 @@ For ViTE there is three documentations that can be found in documentation folder
 
 The first one is the user manual which explain ViTE and its features.
 
-The two other ones are for developers : this is the technical manual and the Doxygen generated doc. The technical manual explains how ViTE is coded and the Doxygen explains the classes and functions more in details.
+The two other ones are for developers: this is the technical manual and the Doxygen generated doc. The technical manual explains how ViTE is coded and the Doxygen explains the classes and functions more in details.
 
 For Doxygen, it is necessary to have epstopdf for the latex version. You can install it with the package texlive-extra-utils.
 Also, install the dot program for graphics from the package graphviz.
 
-The doxygen documentation can be compiled by the command : make doc.
+The doxygen documentation can be compiled by the command: make doc.
 
 
 *******************
 SUPPORTED PLATFORMS
 *******************
 
-For this release, the following platforms have been tested on :
+For this release, the following platforms have been tested on:
 - Ubuntu 8.04 / 8.10 / 9.04 / 10.04.
 - Windows Xp/Vista.
 - Mandriva linux one 2009 kde (under virtualbox).