Clean up TaskGroupPagerAdapter instantiation exception handling in TaskListActivity

[lemonboston]

There is this not too nice piece of code (below) in TaskListActivity, make it cleaner.

try
{
    mPagerAdapter = new TaskGroupPagerAdapter(getSupportFragmentManager(), mGroupingFactories, this, R.xml.listview_tabs);
}
catch (XmlPullParserException e)
{
    // TODO Automatisch generierter Erfassungsblock
    e.printStackTrace();
}
catch (IOException e)
{
    // TODO Automatisch generierter Erfassungsblock
    e.printStackTrace();
}
catch (XmlObjectPullParserException e)
{
    // TODO Automatisch generierter Erfassungsblock
    e.printStackTrace();
}

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(This is taken out of #613 as an independent change.)