Don't deregister all migrations when flushing cache, only the missing ones.
Fixed indentation.
Merge branch 'master' into dont_deregister_on_flush_cache

* master:
  Field collection item - Fixed host entity fetch method.
  Menu items support - Added default value for items with no weight.
Revert "Fixed indentation."

This reverts commit e1727a341a6634b4b26c994204848e895bd2f308.
Revert "Don't deregister all migrations when flushing cache, only the missing ones."

This reverts commit 508d50da051dd28cb2f1464490b116e005e6113c.
Defined migrations to hook_migrate_api. Now we register defined ones and de-register missing ones on hook_flush_caches.
Removed orphan migrations de-registration, refactored yaml migration fetching to its own function, added static variable for yaml functions.
Renamed get_migrations_from_yamls() to migrate_default_content_fetch_migrations()
Merge pull request #7 from aguasingas/dont_deregister_on_flush_cache

Don't deregister all migrations when flushing cache, only the missing ones.