Set file dialog's default location to user's home directory

Since Desktop folder should not contain any binary or text data,
we should rather open home directory by default.
Fix segmentation fault after saving the profile in profile editor

The segmentation fault was caused by the static QFileDialog in
QtHelpers::GetKVPath() while its parent was being removed. We
should use non-static instance of QFileDialog to workaround this.
The other problems were caused by the chaos in bools set by the
ProfileEditor.
Merge pull request #60 from Kuci/master

Set file dialog's default location to user's home directory