Add details of matching builds. Fixes issue #17

Less than 10 matches:

> $ mozdownload -t tinderbox --date=2013-04-08
Retrieving list of builds from https://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-macosx64
Found 3 builds: 1365415768, 1365465695, 1365477812
Downloading from: https://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-macosx64/1365477812/firefox-23.0a1.en-US.mac.dmg

More than 10 matches:

> $ mozdownload -t tinderbox
Retrieving list of builds from https://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-macosx64
Found 143 builds: 1362910146, 1362957227, 1362971147, 1362996586, 1363019027 ... 1365627905, 1365637809, 1365674965, 1365693248, 1365708064
Downloading from: https://ftp.mozilla.org/pub/mozilla.org/firefox/tinderbox-builds/mozilla-central-macosx64/1365708064/firefox-23.0a1.en-US.mac.dmg