Add basic support for linking to local files.
Fixed many Ruby warnings when running prawn under 'ruby -w'

* places where variables were shadowed
* places where instance variables are not initialized
* places with mismatched indentation
* places where deprecated methods are used
* places with unused variables
Merge pull request #342 from dougjohnston/master

Add basic support for linking to local files
add local link support to parser, builds on #342
Merge pull request #559 from crazymykl/local_links_in_parser

add local link support to parser, builds on #342
Merge pull request #554 from gettalong/ruby-warning-fixes

Fixed many Ruby warnings when running prawn under 'ruby -w'
Merge pull request #553 from gettalong/stroke-axis-implementation

Implementation of the stroke_axis helper method
Whitespace cleanup
Unknown HTML-esque tags are now ignored

This also has the effect that using unescaped <, > and & inside of text
that uses inline formatting is now possible.