opm: revamp options

[un-def]

• document verbose option
• fix and document version option
• disable auto abbreviation

auto_abbrev was the reason -v (version option) didn't work as intended; it was treated as an abbreviated --verbose option. Since abbreviated options (e.g., --cmd → -c, --install-dir → -i) hadn't been documented, it's safe to disable this feature. However, --verbose → -v abbreviation is so ubiquitous that it's worth allowing explicitly. For the same reason, --version is abbreviated to -V.

[mparada-suva]

Hi! I'm also interested in this PR and have a suggestion. Right now the verbose flag only affects the curl call in do_upload function. I believe it would be better if it would apply to all curl calls since the verbosity is most practical when debugging. I suggest the verbose flag to also affect other curl calls:

• opm/bin/opm

  Line 1190 in 315e56b

  my $cmd = qq/curl -sS -i -A '$UserAgent' '$url'/;

• opm/bin/opm

  Line 1300 in 315e56b

  shell "curl -A '$UserAgent' -o '$dist_file_path' -D '$header_file' '$url'";

• opm/bin/opm

  Line 2110 in 315e56b

  my $out = `curl -i -sS '$url' 2>&1`;

• opm/bin/opm

  Line 2139 in 315e56b

  my $out = `curl -i -sS '$url' 2>&1`;

What do you think?