Don't return freed memory from wkhtmltopdf_phase_description and wkhtmltopdf_progress_string.
( https://code.google.com/p/wkhtmltopdf/issues/detail?id=1086 )
Merge branch 'master' of https://github.com/antialize/wkhtmltopdf
Merge pull request #22 from poizan42/master

Don't return freed memory from wkhtmltopdf_phase_description and wkhtmltopdf_progress_string