Fixes #8095.

For reference, here is the discussion about the mapping being
incorrect:
http://rubyforge.org/pipermail/tzinfo-users/2012-November/000114.html

Time#at no longer raises an error for large values so we can remove
the rescue clause from ActiveSupport::TimeZone#to_f.

Correcting some confusion. Pago Pago is part of American Samoa, not Samoa. Further, Samoa and Tokelau jumped across the IDL from Dec 29 to Dec 31, 2011 switching from UTC-11 to UTC+13. American Samoa did not make the change and remains at UTC-11. Pacific/Fakaofo and Pacific/Apia are in TZInfo and documentation about the dateline change is in austalasia at IANA.

The system timezone DST jump hour should not be blacked out by Time.zone.parse if current Time.zone does not do the jump at that time.

Fixes #5559.

Removed some useless docstrings and no-doc'ed some.

This wasn't a problem when require_tzinfo was only called from TimeZone#initialize, but now it's being called for every lookup to TimeZone.[] (via lazy_zones_map)

TimeZone lookup can occur when unmarshalling TimeWithZone objects, which is where I first saw the big slowdown (500ms for each Rails action that loaded from Rails.cache)

Fix tzinfo require (it broke test_raises_when_an_invalid_timezone_is_defined_in_the_config in railties)

[#4979 state:committed]

[#4942 state:committed]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Georgetown TimeZone is now mapped to "America/Guyana" instead of "America/Argentina/San_Juan" [#1821 status:resolved]

Fix bug that causes TimeZone.seconds_to_utc_offset to returns wrong offset when hour < 0 and not in hundreds [#3741 status:resolved]
Signed-off-by: NJosé Valim <jose.valim@gmail.com>