Torrent Queuing for Botched torrent (#83)

* Implement a queue for handling failed torrent

* Add checks for getting slots

* Few other cleanups, change some function names

internal/request/errors.go

@@ -1,35 +0,0 @@
-package request
-
-type HTTPError struct {
-	StatusCode int
-	Message    string
-	Code       string
-}
-
-func (e *HTTPError) Error() string {
-	return e.Message
-}
-
-var HosterUnavailableError = &HTTPError{
-	StatusCode: 503,
-	Message:    "Hoster is unavailable",
-	Code:       "hoster_unavailable",
-}
-
-var TrafficExceededError = &HTTPError{
-	StatusCode: 503,
-	Message:    "Traffic exceeded",
-	Code:       "traffic_exceeded",
-}
-
-var ErrLinkBroken = &HTTPError{
-	StatusCode: 404,
-	Message:    "File is unavailable",
-	Code:       "file_unavailable",
-}
-
-var TorrentNotFoundError = &HTTPError{
-	StatusCode: 404,
-	Message:    "Torrent not found",
-	Code:       "torrent_not_found",
-}