Replace all occurrences of data.page with current_page.data

see https://github.com/middleman/middleman/issues/912
Merge pull request #914 from krautcomputing/replace_data_page_with_current_page_data

Replace all occurrences of data.page with current_page.data
Add more nested data tests, actually get simplecov to run
how do i paren?
write some file change and deletion tests for better data coverage
Refactor some of i18n for better codeclimate scores. In the process, make nested i18n files work like rails
Fix #823-2 to allow only one extension on localized views
Make Sitemap::Store#strip_away_locale actually do something
fix up simplecov, add coveralls
update changelog
Merge pull request #917 from joallard/i18n_pages

Fix #823-2 to allow only one extension on localized views
Fix ignoring layouts from the sitemap when the source directory has been set to something other than 'source'. Fixes #896.
Merge branch 'master' of github.com:middleman/middleman
Micro-optimize some regexes
Add an "empty" template and let template classes override the "Gemfile" template.

Custom template classes can define "self.gemfile_template" to return the path to their own Gemfile template, without having to reimplement our generate_bundler! task.
Fix changelog
Merge pull request #920 from bhollis/empty

Add an "empty" template and let template classes override the "Gemfile" template.
break apart some methods to make code less complex
Merge branch 'master' of github.com:middleman/middleman
fix builder not cleaning empty directories
layouts_dir is now configurable. Closes #899