letitbit: file ID in long URL format is not always 8 digits
core.sh (get_filesize): return proper error
plowdown: ignore "MODULE_xxx_DOWNLOAD_SUCCESSIVE_INTERVAL" during checking

Hosters only enforce wait times for actual downloads, so we can ignore
them while checking links for availability.
mirorii: upstream updated, module rewritten
depositfiles: extend accepted domains, also accept HTTPS links
depositfiles: add probe support
turbobit (probe): cosmetics, use consistent style in probe functions
uploaded_net: add probe support
depositfiles + uploaded_net: add (empty) PROBE_OPTIONS

This ammends the commits
ad54e71c81d11523e744440d2cb21057903008c6
09522fe93865560b6d976cc69d4284f4e5a59c26
dl.free.fr: add probe support
dl.free.fr: fix, add missing MODULE_DL_FREE_FR_PROBE_OPTIONS definition
core.sh: add strip_html_comments new API

This could be useful for indexed (html block) extraction functions like grep_form_by_order or grep_script_by_order.

+ minor cosmetics for create_tempfile() and random()
zippyshare (download): upstream modified, fix
extabit: add probe support

Initial patch: Stefan Meier
plowprobe: add bash completion

+ minor changes (fix/bashism)