A+C: add author, rename contributor to a real name

Renamed from github user to use my real name in CONTRIBUTORS, added my name
to AUTHORS.

Change-Id: I671638f1525d44bcc2b0a08d0dcff6adb1717510
GitHub-Last-Rev: b989e185de9ad2d1207085043fcdc821d851c562
GitHub-Pull-Request: golang/go#29823
Reviewed-on: https://go-review.googlesource.com/c/158540Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

AUTHORS

@@ -1304,6 +1304,7 @@ Sven Almgren <sven@tras.se>
 Sylvain Zimmer <sylvain@sylvainzimmer.com>
 Syohei YOSHIDA <syohex@gmail.com>
 Szabolcs Nagy <nsz@port70.net>
+Taavi Kivisik <taavi.kivisik@gmail.com>
 Tad Fisher <tadfisher@gmail.com>
 Tad Glines <tad.glines@gmail.com>
 Taj Khattra <taj.khattra@gmail.com>

CONTRIBUTORS

@@ -715,7 +715,6 @@ GitHub User @OlgaVlPetrova (44112727) <OVPpetrova@gmail.com>
 GitHub User @pityonline (438222) <pityonline@gmail.com>
 GitHub User @pytimer (17105586) <lixin20101023@gmail.com>
 GitHub User @shogo-ma (9860598) <Choroma194@gmail.com>
-GitHub User @tkivisik (13732144) <taavi.kivisik@gmail.com>
 GitHub User @uhei (2116845) <uhei@users.noreply.github.com>
 GitHub User @uropek (39370426) <uropek@gmail.com>
 Giulio Iotti <dullgiulio@gmail.com>
@@ -1773,6 +1772,7 @@ Sven Blumenstein <svbl@google.com>
 Sylvain Zimmer <sylvain@sylvainzimmer.com>
 Syohei YOSHIDA <syohex@gmail.com>
 Szabolcs Nagy <nsz@port70.net>
+Taavi Kivisik <taavi.kivisik@gmail.com>
 Tad Fisher <tadfisher@gmail.com>
 Tad Glines <tad.glines@gmail.com>
 Tadas Valiukas <tadovas@gmail.com>