Merge pull request #701 from DatekWireless/master

Update the documentation to refer to PageGeometry in PDF::Core in the pdf-core gem.
Add rubocop to the test suite.

We ignore any currently failing cops to keep the build passing, in the
future we can fix these issues one at a time or confirm that we don't
care to follow a particular style.
Disable encoding check in rubocop
Merge pull request #703 from prawnpdf/rubocop

Add rubocop to the test suite. Closes #664
Enable and fix UTF-8 encoding comments
Remove Encoding cop comment from .rubocop.yml
Merge pull request #705 from prawnpdf/encoding-utf8

Enable checks for and fix UTF-8 encoding comments
Revert UTF-8 encoding in files that where explicitly encoded ASCII-8BIT
Enable trailing whitespace rubocop check
Remove trailing whitespace
Merge pull request #706 from prawnpdf/trailing-whitespace

Trailing whitespace
failing test case for issue 562
Merge pull request #708 from prawnpdf/issue_562

failing test case for issue 562