Add basic support for linking to local files.
Add multi-row header support
Fix additional table rows height logic
Fix failing tests
First attempt at specs for multiple-row headers
added spec for issue #502 - works without problems with the current code
fixes #502
Fix github #537 : force text rendering mode for templates

Add method forget_text_rendering_mode! to drop the text state when
working with templates.
Merge pull request #538 from kuroneko/master

Fix github #537 : force text rendering mode for templates
Merge pull request #535 from hbrandl/issue_502_fixed

fixes issue #502
Use the current font style in a cell.

When no font style is given for a cell, use the current one.
This is especially relevant for dfont fonts, where the same
font path refers to multiple fonts.

Without this fix, when using a global style for a dfont font,
it is lost in the table.
Ruby 1.8-style hash syntax to maintain compatibility
Cleaned whitespace
Any valid destination can now be an outline destination

Before only simple references to pages could be done. Now, instead
of using an Integer for the :destination key, it is possible to
use an Array with a custom destination (and such an array can
easily be generated with the various #dest_* methods).
Merge pull request #552 from gettalong/outline-destination-enhancement

Outline destination enhancement (backwards-compatible code, tests and documentation)
Whitespace cleanup
Implemented the #stroke_axis helper method based on the one from the manual

Additional options allow moving the axis to another point, setting the
color, and more.
Whitespace cleanup
Updated the manual to use the (now) built-in stroke_axis method
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