Thanks to Slawek Puklo puklos@sdf-eu.org for pointing out that htmlentities() converts too many entities. Apparently it causes problems with characters above ASCII 127 and is overkill for our needs here anyway

• core/string_api.php
  (string_display): use htmlspecialchars() instead of htmlentities()
  (string_textarea): use htmlspecialchars() instead of htmlentities()
  (string_attribute): use htmlspecialchars() instead of htmlentities()
  (string_url): use rawurlencode() instead of htmlentities(urlencode())

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2017 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9