simplify some code with Hash#fetch
move path handling in pages to the `path` method, as in posts
With the move of path handling, Page#to_liquid can be simplified
simplify coderay option handling
simplify Site#initialize
Support missing kramdown coderay option
Posts: move slug to title in a separate method
Move #to_liquid to Convertible
remove no-longer needed LSI accessor

LSI has been moved to another class (Jekyll::RelatedPosts),
but this was left in Post.
refactor Include tag file validation

Split validation into a separate method, and give a more
descriptive error on symlinks.
coding style preferences (@parkr)
Post + Page: extract real path retrieval into separate method (@parkr)
Convertible#to_liquid: allow an alternate attribute set to be passed
Merge branch 'master' into minor-refactors
improve error handling in include tag

* Reduce condition to one-liner
* Remove `self`
* Implicit return value
* Explicit error message for symlinks
include: more helpful error message for symlinks
Clarify that --config flag can take multiple files
Merge pull request #1474 from mgp/master

Clarify that --config flag can take multiple files
Update history to reflect merge of #1474
Merge pull request #1341 from maul-esel/minor-refactors

Minor refactors