Introduce new SpanishDict service implementation

This service supports English and Spanish, with text chunks as long as
200 characters.
Add SpanishDict.com to add-on readme

List this with the other services.
Website documentation for SpanishDict

This adds a page for SpanishDict, covering mostly the same information
as the other online services.
Default to Spanish for SpanishDict

This makes sense and is in the same spirit as the Ekho default.
Lint Yandex.Translate service implementation

Fixes redefinition of the text variable in run() and removes unneeded
pylint comment.
Merge branch 'add/spanish-dict' into develop

Adds support for SpanishDict.
Linting for Ekho service implementation

Brings this up to PEP8 standards.
Uneeded pylint continuation disable

Removes the pylint declaration on remaining service files; this is no
longer needed.
Workaround for broken Korean in Ekho

Ekho seems to only accept Korean when using the lowercase form, so that
is what we can pass.