#39: improve authinfo/netrc parsing and support --netrc-machine=K (default=AWS)
#39: add Git credential helper support with --credential-helper
#39: when parsing netrc files, skip blank lines (no tokens produced)
#39: clarify Net::Netrc license
merge netrc parser from user
fix bad code related to --credential-helper
add --batch=(last object from previous batch) --max-keys=NNNN