Suggest tags while typing tags out

[mruac]

This endpoint in the client API has been recently added and announced since version 500 of the Hydrus Network client API.
/add_tags/search_tags
https://hydrusnetwork.github.io/hydrus/developer_api.html#add_tags_search_tags

To consider:

• Check for Hydrus version and list all supported features before searching tags when an API key is added on the main page
• How will the suggested tags display using Bootstrap CSS? A combination of Popover and List group?

[mruac]

An initial working commit has been added in autocomplete-tag-suggestion-feature branch.

Please let me know how it feels, it may need tweaking with how frequent and how it requests the tag to search with.

A commit checking the availability of the /add_tags/search_tags endpoint will need to implemented to prevent errors.

[mruac]

Merged into master.