Doc bug: example/README gives incorrect command syntax

[jimav]

I'm an Alien newbie, trying out the examples in the example/README . However those examples fail with

unable to read .../example/alienfile

because the commands shown omit the --file option before the alienfile path. For example, the second example given in example/README is

% af install --type=share --prefix=/tmp/foo xz.alienfile

but should be

% af install xz.alienfile --type=share --prefix=/tmp/foo --file xz.alienfile

FWIW I'm using af command version 0.18

[plicease]

Thank you for reporting this, #400 should address it!