Added code to show list of domain overrides for instances.

- Added list of Domain overrides by priority, items in the list are clickable links to a domain containing instance override.
(cherry picked from commit d15b7b6)
Moved instance related code from get_node_info to a new method.

- Moved instance related code from get_node_info to a new method "get_instance_node_info"
- Added spec tests for the new method "get_instance_node_info"
(cherry picked from commit 0dc3f14)
Made further changes to list of overrides on instance summary.

- Changed links in the list to go to an Instance object in the domain that was clicked on. When a domain in the list is clicked, open parent nodes of an instance in the tree.
- Added helper method to determine domian name to be displayed on the list.
- Changed view to not create a link for the Domain that user is currently on in list of overrides.
(cherry picked from commit 0701888)
Changes to show list of overrides on method/class summary.

- Added support to show list of overrides for Automate class and method on their respective summary screens. Moved code that sets domain overrides for instance/class/method records into one common method.
- Moved common view code to display list of overrides for class/instance/method into a common haml view. List of overrides is only displayed where any overrides exist accross domains. Rows in the list have a link to go to the respective object in the domain that is being clicked on, there is no link on the row with a domain that user is currently on.
- Fixed existing spec test to call correct method ot test get_instance_node_info and added spec tests for get_method_node_info & get_class_node_info methods.
Some further tweaks to the text/titles.

- Use model method domain to determine record's domain name.
- Fixed spec tests, added domain key to Class/Instance/Method objects.
Merge pull request #317 from h-kataria/ae_display_list_of_overrides_accross_domains

Added support to display list of overrides for Class/Instance/Method objects across domains