PDF export: Use different font for titles
Add UnicodeUtils gem to address issues with case conversion of multibyte characters (e.g., accented letters in SmallCaps titles):

Ruby's #downcase and #upcase methods don't convert case on multibyte characters because it is locale dependent.
Added rtfile setting for PDF export header text
PDF export: Added a flag that will add an info page to the end of the pdf that provides a list of all commits and commit messages.
Updated interface to validation methods to make testing easier: Pass in files instead of file paths so that we can simulate files using StringIO.
PDF export: don't indent id_paragraph's first line.
PDF export: Convert all escaped unicodes to characters.
PDF export: differentiated header and footer format between primary and non-primary repos
PDF export: Verify that no temp gap_mark text is left
PDF export: Differentiate how id_title1 is rendered between primary and non-primary repos.
PDF export: don't include subsequent ellipses in gap_mark red colouring. Only leading ellipsis. This avoids long runs of red coloured text connected via ellipses.
Move parsing of :record_marks, :gap_marks, and :subtitle_marks from vgr-repositext into repositext.
Fix naming of kramdown validation parsers
Added documentation
Updated Repositext::Validation::Validator::KramdownSyntaxAt:

* better handling of first :record_mark in a document
* fixed check of :record_marks with no text between them
* fixed check that all :record_marks have to be followed by 2 newlines
Added specs for Repositext::Validation::Validator::KramdownSyntaxAt
Added framework for Repositext::Validation specs.