Allow to have options that can be specified more than once

[rubik]

As hinted in https://github.com/docopt/docopt.hs/issues/24#issuecomment-153082237

there is currently no way to get a list out of options. There is getAllArgs, but it only works for positional arguments.

[simonmichael]

Related, it seems that getArgCount returns 1 for -v -v or -vv, contrary to the haddock (and the second occurence is treated as an argument instead of a flag).

[moll]

Bump. ;)

[moll]

I have fixed this in my fork with https://github.com/moll/hs-docopt/commit/5a33206f7095ffb34adfd86293b4b2931d88ecb2. I also did other things to make developing easier for me, so feel free to cherry-pick those commits you deem useful.