dl-and-commit.sh: use http, detect latest version
extract.sh: fix mode of extracted files
NSA 3.5a7

From https://noscript.net/nsa/latest/noscript-3.5a7.xpi

Last-Modified: Wed, 03 Dec 2014 23:04:33 +0000
File size: 178541 bytes

md5: 9596fcc9c891c95ac9192a249eb4c937
sha256: a12a524a3d24bfbe11720c21aa261618d56fde8c2bb30e22f0a5dc0d4cda1879