test/integration: add sharing test

http://camlistore.org/issue/462

Change-Id: If7642eef597bf1d81a88738c1b831f582d7ace30
make.go: enable if_mods_since flag

And use the flag in integration tests.
devcam server already uses it.
Does not fully work yet with devcam test.

Change-Id: I0dbd2b28ff60090133abf0b9578e33d5788a6603
android: Add QR code scanning to SettingsActivity.

Import src/com/google/zxing from
https://github.com/zxing/zxing/android-integration/src/ at revision:

    commit 7d35bd0bddbe84185b9f79c5cb07749a8767c952
    Author: Sean Owen <srowen@gmail.com>
    Date:   Wed Aug 6 09:05:22 2014 +0100

Uses zxing dervied barcode scanner apps to do the heavy lifting.  If the
user does not already have the app installed a dialog will open that
directs them to install it from the Google Play store.

Addresses https://camlistore.org/issue/372

Change-Id: Ic398b77cd9795aca533be101b2ebcd5631cc7f20
Merge "android: Add QR code scanning to SettingsActivity."
Merge "test/integration: add sharing test"
Merge "make.go: enable if_mods_since flag"
client&camput: use cmdmain.Stderr for logging

And use -verbose in tests, for easier debugging.

Change-Id: Iac5e1a8e9c987f82fc221ce73c7e3ca10a86a924
Don't use untagged struct literals.

Change-Id: I115592d815e6419eeffb5f23c3df953068d27371
Update goauth2 to f06a85362aa5

Change-Id: I581d449099b6201dc78593c3394fa3ae0954e0c3
changeset:   75:f06a85362aa5
tag:         tip
user:        Brad Fitzpatrick <bradfitz@golang.org>
date:        Tue Aug 12 13:58:32 2014 -0700
summary:     oauth: clean up docs, code, fix data race, don't send client_secret in two places
Merge branch 'master' of https://camlistore.googlesource.com/camlistore
android: logging/whitespace cleanup.

Addressing feedback from https://camlistore.org/r/3416

Change-Id: Ied7e86e12861ec27be0e2f3d41aefcd92ec5d1a3
Merge "client&camput: use cmdmain.Stderr for logging"
Make Google oauth2 support work again.

Change-Id: I7f5f3c714c7385685c283fec5362db5ca1c31f81