Fixed some formatting issues in chapter two

Because of a syntax error (missing new line), code sections
were not being ignored by RedCloth. That meant that macros like
RCLASS(value) were being interpreted as an acronym. RCLASS(value)
would become RCLASS and in theory tooltip with "value" would appear
on mouseover.

Additionally, using backticks to format code inline in a paragraph
does not work across line breaks. Any multi word inline code fragments
must be on the same line.
Merge pull request #6 from hamiltop/fix_formatting_issues_in_chapter_two

Fixed some formatting issues in chapter two
replace map! in _plugins/rhg_textile_converter.rb

Jekyll is complaining about using map! on an Enumerable.
By chaining the methods together differently we can avoid the
destructive map.
Merge pull request #7 from hamiltop/fix_rhg_textile_converter_plugin

replace map! in _plugins/rhg_textile_converter.rb