weekly release 2.6dev
MDL-40402 libraries: Replace get_system_context() with context_system::instance() in core
MDL-40402 unittests: Make sure get_system_context() throws a deprecated warning
MDL-40402 libraries: Deprecate get_system_context()
MDL-40402 libraries: update the mistake in comment
MDL-40403 libraries: Deprecate get_parent_contexts()
MDL-40403 tests: Fix pointless assertion
MDL-40404 Libraries: Deprecated get_parent_contextid()
MDL-40405 libraries: Deprecate get_child_contexts()
MDL-40405 libraries: Fix PHPDoc and debugging assertion
MDL-40406 libraries: Deprecate create_contexts()
MDL-40406 libraries: Deprecate cleanup_contexts()
MDL-40406 libraries: Deprecate build_context_path()
MDL-40406 libraries: Deprecate rebuild_contexts()
MDL-40407 Libraries: deprecated preload_course_contexts
MDL-40404 Libraries: Moved DEVELOPER_DEBUG outside loop
(cherry picked from commit d519c222e29ed5873f53b406c6046e9339cc20b7)

Conflicts:

	lib/tests/accesslib_test.php
MDL-40427 Libraries: Deprecated context_moved in favor of context::update_moved()
MDL-40425 libraries: Deprecate context_instance_preload()
MDL-40425 libraries: Remove context_instance_preload() from core
MDL-40429 - Libraries: Deprecate get_contextlevel_name().