Cache the extname regexp in Converters::Markdown and Textile
Cache variables that won't change through the life of an object
Only compile the Converter#matches regexp when asked for
Add test for Document#basename_without_ext
Only run script/bootstrap in stackprof if stackprof executable isn't there
Cache the `@includes_dir` in each instance so the method isn't called all the time
Don't print the location of the stackprof executable
Only re-run the stackprof if I delete the prof output file.
Ignore the stackprof tmp files.
Pass the context on to IncludeRelativeTag#page_path
Merge pull request #2994 from jekyll/fixes-from-benchmarking