plowdown, plowprobe: fix, incorrectly identified binary file

Credits go to Matthew Stanfield.
Fixes issue 1170.
plowdown, plowup: add --cache switch

revision f3130ecf495d7ab926d49b73d90404a07950c8ce
introduced module storage space.

There are three possible values:
- none
- session (default)
- shared

See man pages for documentation.
rapidgator (login): Handle rare 'heavy usage' issues

These can be:
- Enforced wait time before the login
- A custom Rapidgator Captcha (not the usual Solvemedia one)

See also issue 1105
plowdown: add log_notice message for unused command line option(s)

Might be useful!
keep2share (upload): check for expired token
man pages: fixes (typos, spelling and a hyphen-encoding error)
uptobox (download): fix, upstream changed
modules: drop uneeded shebang line

The shebang is used if you run the script directly as an executable file.
core.sh (log_*): minor, make it smaller (faster?)
core.sh: don't read directly LIBDIR variable anymore

Make LIBDIR readonly in plow* script.
Change prototype for: get_all_modules_list() and log_report_info().
anonfiles: fix upload (new api url)

+ use official API for probe
keep2share (download): add premium support
plowdown: fix MODULE_xxx_DOWNLOAD_FINAL_LINK_NEEDS_EXTRA with bash 4.3

Write properly array indirection.

<code>
f() {
  local name=$1
  local -a arr="$name[@]" # weird assignment
  for e in "${!arr}"; do
    echo "element: '$e'"
  done
}

aaa=(1 2 3)
f aaa
</code>

Works with bash 4.2 but not 4.3
rapidgator (login): fix, reparse login cookie properly

Fixup for d39be784fecdcc0b36de92d94bc14a56f2f0296e
rapidgator (download): Consider quota error for premium users
core.sh (print_module_options, get_all_modules_options, get_module): use array reference

Using an array is better than giving a multi line variable.
core.sh (captcha_process): better call for identify (ImageMagick)
Makefile: uninstall bash-completion files

Fixes issue 1177.
plowup: fix module_exist()

Regression introduced in commit:
core.sh (print_module_options, get_all_modules_options, get_module): use array reference
revision 08993bd73fd8a01a2cbae6bb6d31ff6b4879f77a
oboom: fix login

Fixes issue 1181.