download.sh (mark_queue): small rework

Filename now appears before the marked link. It's more logical and follow plowlist behavior.

|$ cat my_list.txt
|http://www.yshare.com/3102022
|http://www.yshare.com/3102591
|http://www.xshare.com/acvjre85
|
|$ plowdown -q -l my_list.txt
|...
|
|$ cat my_list.txt
|# Filename1.rar
|#OK http://www.yshare.com/3102022
|# Filename2.rar
|#OK http://www.yshare.com/3102591
|#NOMODULE http://www.xshare.com/acvjre85
zalaa: add list support
letitbit: minor, fix wrong copyright
mediafire (download): fix, upstream modified
core.sh: enhance process_options()

Changes:
1. Split parse_transfer_speed into two functions:
- check_transfer_speed: basic check of argument
- translate_size: generic purpose parsing function
Usual unit rates suffix are supported: K, kB, KiB, KB, MiB, MB, GiB, GB.
This fonction is added to plowshare API (so, it can be called in modules).
Example:
translate_size "349.0 MB" => 349000000 (stdout)

2. Fix when $OPTIONS is empty to $STEP <= 0

3. Add a notice message when specifying an argument to a non-argument option
mirrorcreator (list): fix (uptream modified)
sendspace (upload): quick fix, DESTINATION_DIR is now located is the form action URL
core.sh (translate_size): consider tabs too
bitshare (download): fix 'dead link' regression

Introduced in:
bitshare (download): add check for file availability ($CHECK_LINK)
revision 5a252a24e4195ea78897b6f4ee2832f961d9f58c
plowprobe: first version

Idea here is to be able to get for information about download links.

Alike download/upload/delete/list module functions:
- probe is a new standalone module function
- probe can be enabled through modules/config
- probe can have (module) dedicated options (like --auth ..)

You can see plowprobe as an enhanced "plowdown --chech-link".

| $ plowprobe http://rapidgator.net/file/95340367
| # Foo_Bar-2013.rar
| http://rapidgator.net/file/95340367
|
| $ plowprobe http://rapidgator.net/file/95340367 --printf %s
| 99840000

Plowprobe handled capabilities are: file name, file size, file hash.
Depending modules metadata are available or not.

Documentation will come later, here are --printf interpreted sequences (notice that only alive links are being processed):

%c: probe return status (0, $ERR_LINK_DEAD, ...)
%f: filename or empty string (if not available)
%F: alias for "# %f%n" or empty string if %f is empty
%h: filename hash or empty string (if not available)
%m: module name
%s: filesize (in bytes) or empty string (if not available). Note: it's often approximative.
%u: download url or empty string
%n: newline
%t: tabulation
%%: raw %

As "proof of concept", here are few modules implementing it:
- bitshare
- rapidgator
- rapidshare
- sendspace
- zalaa
- zippyshare
rapidgator: fix, remove temp debug