better API for passing document parameters

based on suggestion from @jordanbyron
the options hash can now include a documents hash - these parameters are
passed down to prawn, so any other options avaolable via Prawn can be
used (such as background:, info:, optimize_objects, etc. - see
http://prawn.majesticseacreature.com/docs/0.11.1/Prawn/Document.html#method-c-new
)
Revert "fix format error"

This reverts commit 02407a1109db7b4954fc69d6f47a19e550ced0cd.
Revert "Add landscape option to the document"

This reverts commit 81ba4ac5182c814abe11707681b5d46112bff4da.
Update hello_labels_landscape.rb

remove legacy API from landscape example
Merge branch 'landscapable'
finish merging