title: how to run qtcreator on linux? 2 versions installed
body: <p>I had qt 4.8.0 installed on Ubuntu.
  It's qtcreator executable is in /usr/bin/ and this version runs when I type 'qtcreator' in terminal.
  Then I've installed qt 5.2.0 in my home directory.
  I don't know how to run it. </p>