#36 batch of small fixes for PDF support

[Benoit Pierre]

[PATCH 1/3] pdf: make sure we don't treat filenames as options

Use '--' after option arguments.

[PATCH 2/3] pdf: make sure all subprocesses are reaped:

Wait on them so we don't leave zombie processes.

[PATCH 3/3] pdf: minor code simplification:

for line in fd.read().splitlines() => for line in fd

[Benoit Pierre]

Oups, forgot one wait, here is an updated patch.