date: more sensible date numbering

- 1. mm-dd-yy is used only in North America nowhere else,
     no offense but it looks most illogical.
     dd-mm-yy and yy-mm-dd are much more logical
- 2. make 13 -> 2013 to not confuse it as a date
- 3. make it YYYY-MM-DD so that in listings,
     nightlies can be arranged increasingly/decreasingly

Earlier we had Apr-17-13
Now we have 2013-04-17

Imho it's more sensible, logical and methodical.

PS2: Typo in commit message
PS3: Commit msg formatting

Change-Id: Ia59c72634a9e08b1716da8e6d8715affa52bba65
Signed-off-by: ChampionSwimmer <android@championswimmer.tk>