Fix CI: json_view access tests without exceptions and on clang 3.6

- ci_test_noexceptions: the element access tests compare the exceptions
  of json_view and basic_json through exception_of(), which catches them
  outside a CHECK_THROWS; with JSON_NOEXCEPTION the first one aborted the
  test. Compile those comparisons only with exceptions.
- clang 3.6: value-initialize a const json_view, as in the tests of
  json-view/10-view-document.
- Format three new documentation examples with the pinned astyle, which
  the "check" job runs once it gets past the amalgamation step.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/examples/basic_json_view__cbegin.cpp

@@ -15,7 +15,7 @@ int main()
     const auto values = measurements.root();
 
     const int sum = std::accumulate(values.cbegin(), values.cend(), 0,
-                                     [](int total, const json_view & v)
+                                    [](int total, const json_view & v)
     {
         return total + v.materialize().get<int>();
     });

docs/mkdocs/docs/examples/basic_json_view__cend.cpp

@@ -15,7 +15,7 @@ int main()
     const auto records = batch.root();
 
     const bool all_objects = std::all_of(records.cbegin(), records.cend(),
-                                          [](const json_view & v)
+                                         [](const json_view & v)
     {
         return v.is_object();
     });

docs/mkdocs/docs/examples/basic_json_view__type_name.cpp

@@ -13,7 +13,10 @@ int main()
     json_document bad = json_document::parse("[1, 2, 3]");
     json_document failed = json_document::parse("not json", /* allow_exceptions */ false);
 
-    for (const json_view v : { good.root(), bad.root(), failed.root() })
+    for (const json_view v :
+            {
+                good.root(), bad.root(), failed.root()
+            })
     {
         if (v.is_object())
         {