Implemented GET:

/api/v1/languages
/api/v1/languages/id
/api/v1/items
/api/v1/items/id
/api/v1/terms
/api/v1/term/id
Implement read/listen log
Implement mark all as known
Improve mark as known
Attempt to fix DELETE
Updating reading
Restructing library
Refactoring reader into library
More refactoring