Determine the docset type.

- Add a function to get the docset type.
- Modify helm-dash-connections. Now it is a list with docset name,
- connection and docset type.
Add functions to build sql queries.
Doc for `helm-dash-available-docsets'.
Compose sql queries for dash and zdash formats.
Unify the ugly sql code in centralized var.
formatted lists correctly
attempt to make buffer local docsets work
Avoid multiline with sql statements.
Merge branch 'master' into multiple-docset-formats
Change ZDASH sql select query.

Get the ZTYPENAME column.
Add a function to compose the url for a search result.

- Extract the code to a function.
- In ZDASH docsets, we must join the anchor with the filename.
Use esqlite package instead of sqlite.
Update README.
Merge pull request #19 from areina/multiple-docset-formats

Multiple docset formats