Use File#read instead of #readlines.join construct
Revert to #readlines#join, but enclose it in a function

This is necessary to preserve the handling
of \r\n and \n line endings.
rename the new function
use assert_match
#to_sym is called by #symbolize_keys
shorten test code by moving converter instantiation to #setup
add tests for moving of coderay settings for kramdown
Replace directory_watcher with listen.

Directory_watcher consumed ~25% CPU on big Jekyll projects (depending on
the number of watched files), since it polled for changes every second.

Listen is easier on CPU, as it uses directory change notifications
provided by OS (currently OS X and Linux), falling back to polling when
they are not available.
Remove require 'pathname': already included.
Handle destinations outside of source.
Add docs for new Data Files feature
Fix typo in data docs; update section pagination for migrations to correctly point back to data
Rebase on upstream/master; rename file to work with docs_ul includes file
another pass on the documentation of generators

This commit refines the docs contributed in f074bb6.
Add a cucumber feature for variable includes
implement variable retrieval in include tag

Fixes #1464.
Fix code to allow dots in variables
extend feature to ensure it works with parameters as well
Document variables in include tag
Include tag: provide path in case of render error