Remove manual addition of "Etc" timezones

All of the fixed timezones that were added can be found in the file
"etcetera" from the IANA website. Even though we could support these
timezones I think we shouldn't as they are deemed historical along with
"backward".

Additionally, the "Etc/GMT(+|-)\d+" can be confusing as their labels
("GMT+1") have the opposite offset (-3600 seconds).

See ftp://ftp.iana.org/tz/data/etcetera for details.

deps/build.jl

@@ -1,5 +1,13 @@
-import TimeZones: TZDATA_DIR, COMPILED_DIR, fixed_timezones
-import TimeZones.Olson: REGIONS, compile
+import TimeZones: TZDATA_DIR, COMPILED_DIR
+import TimeZones.Olson: compile
+
+# See "ftp://ftp.iana.org/tz/data/Makefile" PRIMARY_YDATA for listing of
+# regions to include. YDATA includes historical zones which we'll ignore.
+const REGIONS = (
+    "africa", "antarctica", "asia", "australasia",
+    "europe", "northamerica", "southamerica",
+    # "pacificnew", "etcetera", "backward",  # Historical zones
+)
 
 isdir(TZDATA_DIR) || mkdir(TZDATA_DIR)
 isdir(COMPILED_DIR) || mkdir(COMPILED_DIR)
@@ -42,16 +50,4 @@ for file in readdir(COMPILED_DIR)
 end
 compile(TZDATA_DIR, COMPILED_DIR)
 
-info("Adding additional FixedTimeZones")
-for (name, tz) in fixed_timezones()
-    parts = split(name, "/")
-    tz_dir, tz_file = joinpath(COMPILED_DIR, parts[1:end-1]...), parts[end]
-
-    isdir(tz_dir) || mkpath(tz_dir)
-
-    open(joinpath(tz_dir, tz_file), "w") do fp
-        serialize(fp, tz)
-    end
-end
-
 info("Successfully processed TimeZone data")

deps/tzdata/utc

@@ -0,0 +1,5 @@
+# Zones specifically for TimeZones.jl
+
+# Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
+Zone	UTC			0 	-	UTC
+Zone	GMT			0	-	GMT

src/TimeZones.jl

@@ -29,7 +29,6 @@ include("timezones/io.jl")
 include("timezones/adjusters.jl")
 include("timezones/Olson.jl")
 include("timezones/conversions.jl")
-include("timezones/fixed.jl")
 
 function TimeZone(name::AbstractString)
     tz_path = joinpath(COMPILED_DIR, split(name, "/")...)

src/timezones/Olson.jl

@@ -6,11 +6,6 @@ import ..TimeZones: TZDATA_DIR, COMPILED_DIR, ZERO, MIN_GMT_OFFSET, MAX_GMT_OFFS
     MIN_SAVE, MAX_SAVE, ABS_DIFF_OFFSET, Time, toseconds
 import ..TimeZones: TimeZone, FixedTimeZone, VariableTimeZone, Transition, Time
 
-const REGIONS = (
-    "africa", "antarctica", "asia", "australasia",
-    "europe", "northamerica", "southamerica",
-)
-
 # Zone type maps to an Olson Timezone database entity
 type Zone
     gmtoffset::Time
@@ -509,8 +504,8 @@ end
 
 function load(tzdata_dir::AbstractString=TZDATA_DIR)
     timezones = Dict{AbstractString,TimeZone}()
-    for region in REGIONS
-        zones, rules = tzparse(joinpath(tzdata_dir, region))
+    for filename in readdir(tzdata_dir)
+        zones, rules = tzparse(joinpath(tzdata_dir, filename))
         merge!(timezones, resolve(zones, rules))
     end
     return timezones

test/runtests.jl

@@ -23,5 +23,4 @@ include("timezones/arithmetic.jl")
 include("timezones/io.jl")
 include("timezones/adjusters.jl")
 include("timezones/conversions.jl")
-include("timezones/fixed.jl")
 include("timezone_names.jl")

test/timezone_names.jl

@@ -5,3 +5,8 @@ names = timezone_names()
 @test length(names) >= 429
 @test isa(names, Array{AbstractString})
 @test issorted(names)
+
+# Make sure that extra timezones exist from "deps/tzdata/utc".
+# If tests fail try rebuilding the package: Pkg.build("TimeZones")
+@test "UTC" in names
+@test "GMT" in names