Add version 0.0.4 of gitdate script, for altering git commit timestamps.

 * Fix timezones east of UTC to do the computations with the signs flipped.
 * Fix the stupid date string parsers to make them more efficient.
 * Add printf statements with the exported variables.
Fix gitdate to make it (sort of) coprocess-friendly and add exec checks.

 * Add checks so that it knows if it has been sourced or executed.
Add git-fix-date script for iterating commits and changings timestamps.
Add script for making the verification of Riseup! server fingerprints less painful.

  * Please don't use this if you don't understand what it's doing.

This script does the following:

  1) Grabs the page from riseup.net which contains a GPG signed list of the
     current server fingerprints (currently this is at
     https://help.riseup.net/en/signed-certificate-fingerprints) and pipes it
     to sed to strip out everything except the GPG signed message.

  2) Asks a keyserver for Riseup's GPG key (specified by full fingerprint).
     TODO: It should really only do this if we don't already have it, I think
     the keyserver-option is 'merge-only' for that.

  3) Prints out the results of doing '$ gpg --verify ' for the message signature.

  4) Prints out the relevant lines from the message (just the hostname and
     certificate hash/fingerprint for status.riseup.net and riseup.net).

  5) Uses OpenSSL s_client to connect directly to status.riseup.net and
     riseup.net and request their certificates, which are then (through
     OpenSSL x509) translated into x509 certs and the fingerprint for each one
     is printed on stdout.

tl:dr; It tells you the purported fingerprints, according to Riseup, and
whether or not that information was verifiable. Then it tells you your current
view of the actual certificates, as your normal web browser would see them. If
these things match, you're probably good, if not, then SomethingBad is
happening.