Fix a build error: explicitly list automake when we need it.

Automake disappeared from the base package list in the gitian rebase, I guess?
Record and check explicit hashes for stuff without sigs.
Make dtar.sh less sensitive to weird character input.
Attempt to check out mingw-w64 deterministically and record its hash.
Fix a path error with gitian-builder in verify-tags.sh
Bump gitian-builder to the new version.
Fix a typo during mingw rename.
Bug #9084: Fetch, hash, and link in msvcr100.dll.
Fix NoScript and PDF.JS urls+hashes.

PDF.JS seems to have dropped FF17-ESR support. :/
Bug #9283: Update NoScript prefs for usability.
Stop relocating build.log on failure.

It seems to confuse people and conflicts with gitian's output messages. Also,
the build now stops, so the logs aren't overwritten anymore.
Bug #9084: Try harder to link against msvcr100.dll
Update ChangeLog for 3.0a3.
Update versions file for 3.0alpha3.
Add Micah's key to https-everywhere's keyring.
Bump gitian-builder version.