specify custom brace style to fix unions

BreakBeforeBraces: Allman apparently includes all styles,
except for AfterUnion (which is false) when using clang-format -dump-config

Source/.clang-format

@@ -19,8 +19,20 @@ AlwaysBreakBeforeMultilineStrings: false
 AlwaysBreakTemplateDeclarations: true
 BinPackArguments: true
 BinPackParameters: true
+BraceWrapping:
+  AfterClass:      true
+  AfterControlStatement: true
+  AfterEnum:       true
+  AfterFunction:   true
+  AfterNamespace:  true
+  AfterObjCDeclaration: true
+  AfterStruct:     true
+  AfterUnion:      true
+  BeforeCatch:     true
+  BeforeElse:      true
+  IndentBraces:    false
 BreakBeforeBinaryOperators: None
-BreakBeforeBraces: Allman
+BreakBeforeBraces: Custom
 BreakBeforeTernaryOperators: false
 BreakConstructorInitializersBeforeComma: false
 ColumnLimit:     100