Update setup.py to use Pillow rather than PIL

PIL is old and broken, using Pillow instead to support modern systems.
Merge branch 'patch-1' of https://github.com/bradleyayers/xhtml2pdf into bradleyayers-patch-1

Conflicts:
	setup.py
Changed PIL to PIllow in requirements.txt

Also renamed requirements.xml to requirements.txt.
Added _trial_temp to gitignore.