Fix apps test

Also get rid of the timestamps from the App type. They have time zone information (now,
they didn't a few days ago when I wrote the code for the first time),
which we currently don't handle. I played with TimeZones.jl, but it currently can't
parse the GitHub time stamp. For now, just delete those fields and revisit that
once TimeZones.jl has been updated to handle this better.

src/apps/apps.jl

@@ -5,8 +5,6 @@ type App <: GitHubType
     description::Nullable{String}
     external_url::Nullable{String}
     html_url::Nullable{String}
-    created_at::Nullable{Dates.DateTime}
-    updated_at::Nullable{Dates.DateTime}
 end
 
 namefield(a::App) = a.id

test/read_only_api_tests.jl

@@ -132,6 +132,6 @@ end
 end
 
 @testset "Apps" begin
-    @test get(app(4123).name) == "femtocleaner"
-    @test get(app("femtocleaner").name) == "femtocleaner"
+    @test get(app(4123; auth=auth).name) == "femtocleaner"
+    @test get(app("femtocleaner"; auth=auth).name) == "femtocleaner"
 end