Changed util.config_changed to allow identifier (per plugin/task), so several config_changed objects can appear in one uptodate field of a task.
Changed '__' to ':' and prepending 'nikola.' to every new use of utils.config_changed.
Now using correct paths.
Fixed spelling.
Forgot sitemap plugin.
fix some bs3 styles here or there

Signed-off-by: Chris Warrick <kwpolska@gmail.com>
force dateutil 2.2 for windows compat

Signed-off-by: Chris Warrick <kwpolska@gmail.com>
Fixed implementation of TemplateHookRegistry's hash function.
Added information about the change to utils.config_changed (#1526).
Merge pull request #1526 from felixfontein/dependency_refactoring

Refactoring util.config_changed and its usage in core plugins
really fix spelling [ci skip]
Extended types of dependencies which posts objects can return.
Post.extra_deps cannot be called from outside anymore.
Next step is to rewrite the functions in Post to allow the page compiler to send extra dependencies (instead of reading them from the Post object) and to add functions which allow to add additional dependencies (via callbacks or directly).
Forgot to add lang parameter.
Moved extra_deps() logic from post.Post to plugin_categories.PageCompiler.
Renamed rest_deps function, and added language parameter.
Made extra dependency system compatible to old extra_deps system.
Added facility to Post object to inject dependencies.
Changed PageCompiler's register_extra_dependencies to get_extra_dependencies, which uses the new utility functions.
Refactored PageCompiler.register_extra_dependencies: split into two functions.
PageCompiler.register_extra_dependencies now emits a warning.
All page compilers in core overwrite this function (so no warning will be displayed).
Moved .dep logic completely into ReST compiler.
Removed default warning for PageCompiler objects who don't override register_extra_dependencies.
Consequently removed overrides of register_extra_dependencies in core compiler plugins which don't do anything.