Replace common_timezones with all_timezones

[pferreir]

Currently, some timezones are not shown in the list, since they are considered to be "deprecated".
Since we don't want to be dependent on the politics of standardization of timezones, and we want to allow users to use the timezone names they're used to, we should start displaying the list of all the timezones.

[pferreir]

Some info i got from the olson timezone db archivesÇ

 > > Ho Chi Minh City aka Saigon is far more populous than Hanoi, so that's
 > > why we use it.  (Just as we use Los Angeles and not Sacramento.   :-) 
 >
 > However, Asia/Jerusalem and not Asia/Tel_Aviv is the official
 > time zone for Israel.

It used to be Asia/Tel_Aviv, but someone reported that Jerusalem's
population is now greater than Tel Aviv's, at least by some measures.
Jerusalem is much better-known, so that was enough to get us to
switch.  If Jerusalem becomes a divided city with different
daylight-saving rules, then we'll need to revisit this issue.

[jose.pedro.ferreira@…]

commit a0203b842a8b11bd2064e224cce8237be5d3d1be
Author: Pedro Ferreira <jose.pedro.ferreira@…>
Date: Thu Feb 18 15:52:56 2010 +0100

[FIX] Replaced common_timezones with all_timezones

• introduces some "non-standard" timezones that were not available;
• solves most problems created by timezone add/remove from the olson "standards";
• fixes #204

[Pedro Ferreira <jose.pedro.ferreira@…>]

In [a0203b842a8b11bd2064e224cce8237be5d3d1be]:

[FIX] Replaced common_timezones with all_timezones

• introduces some "non-standard" timezones that were not available;
• solves most problems created by timezone add/remove from the olson "standards";
• fixes #204