zippyshare (download): upstream updated

Credits go to roadman17.
Closes issue 1208.
plowdown: ignore -O/-J switches in MODULE_xxx_DOWNLOAD_FINAL_LINK_NEEDS_EXTRA

Put a log_debug message for now.
This would requires cURL 7.25.1+ to treat it correctly (using -w '%{filename_effective})
zalil_ru: drop module
plowdown, plowup, plowprobe: fix --no-curlrc option

Closes issue 1215.
uploaded_net (download, probe): detect folder links
keep2share (download, probe): fix detection of deleted files
mediafire: consider HTTPS links
thefilebay: fix download & upload (upstream modified)
letitbit (upload, download): Support for sessions caching

Semantics: Whenever there is a cached session, it is checked
for validity and reused if possible. Credentials provided via
command line or config file do *not* take precedence. Those are
considered only if there is no valid cached session.

Fixes issue 1224
letitbit: Remove pipes to avoid SIGPIPE issues
thefilebay: fix login (upstream modified)