When the input file name has no extension, just ignore the extension
    instead of failing outright. This is useful when /dev/stdin is the input
    filename and there are known to be no dependencies to deal with.
Allow pkg add to read from a pipe or a non-regular file -- so now, all
of the following work:

Installing portmaster-3.17.2... done

Installing portmaster-3.17.2... done

Installing portmaster-3.17.2... done

The special filename '-' means 'read from stdin', but should also read
from character special devices, pipes, fifos, unix domain sockets etc.
Update man page to descripe the special '-' filename meaning 'read
from stdin' and better describe the behaviour when the base directory
for packages cannot be intuited from the filename passed on the
command line.
Fix typo.
Merge branch 'master' into lock-error-msg