Update CONTRIBUTING.md
Account for \n at start of xref in startxref

Although (most) PDF readers seem to cope with an incorrect startxref value
it is off by one and can cause problems with other PDF libraries if they
trust the startxref value (i.e. they don't account for this issue).
Merge pull request #776 from pauln/master

Account for \n at start of xref in startxref
Update php-font-lib requirement
Revert "Update php-font-lib requirement"

This reverts commit ffb51908cb6036a096b25c96a3f65dd30144f893.
Merge pull request #779 from donatj/master

Update php-font-lib requirement with the new 0.2.x release
Merge branch 'master' into dev
Little bit of cleaning up for 0.6.0 final
Merge branch 'master' into dev