Initial commit for 2.0.0
Implement Pdf class
Implement Xvfb support
Implement Image command
Update README and CHANGELOG
Add comments. Add test for empty argument.
Update notes for Windows users
Add proper escaping for input/output filenames
Replace TmpFile with mikehaertl/php-tmpfile
Add more badges to README
Prepare 2.0.0 release
Merge branch '2.0'

Conflicts:
	WkHtmlToPdf.php
Prepare 2.0.1-dev