Make clang-format somewhat compatible across versions

Author: ctiller

.clang-format

@@ -1,57 +1,5 @@
 ---
 Language:        Cpp
-# BasedOnStyle:  Google
-AccessModifierOffset: -1
-ConstructorInitializerIndentWidth: 4
-AlignEscapedNewlinesLeft: true
-AlignTrailingComments: true
-AllowAllParametersOfDeclarationOnNextLine: true
-AllowShortBlocksOnASingleLine: false
-AllowShortIfStatementsOnASingleLine: true
-AllowShortLoopsOnASingleLine: true
-AllowShortFunctionsOnASingleLine: All
-AlwaysBreakTemplateDeclarations: true
-AlwaysBreakBeforeMultilineStrings: true
-BreakBeforeBinaryOperators: false
-BreakBeforeTernaryOperators: true
-BreakConstructorInitializersBeforeComma: false
-BinPackParameters: true
-ColumnLimit:     80
-ConstructorInitializerAllOnOneLineOrOnePerLine: true
-DerivePointerAlignment: true
-ExperimentalAutoDetectBinPacking: false
-IndentCaseLabels: true
-IndentWrappedFunctionNames: false
-IndentFunctionDeclarationAfterType: false
-MaxEmptyLinesToKeep: 1
-KeepEmptyLinesAtTheStartOfBlocks: false
-NamespaceIndentation: None
-ObjCSpaceAfterProperty: false
-ObjCSpaceBeforeProtocolList: false
-PenaltyBreakBeforeFirstCallParameter: 1
-PenaltyBreakComment: 300
-PenaltyBreakString: 1000
-PenaltyBreakFirstLessLess: 120
-PenaltyExcessCharacter: 1000000
-PenaltyReturnTypeOnItsOwnLine: 200
-PointerAlignment: Left
-SpacesBeforeTrailingComments: 2
-Cpp11BracedListStyle: true
-Standard:        Auto
-IndentWidth:     2
-TabWidth:        8
-UseTab:          Never
-BreakBeforeBraces: Attach
-SpacesInParentheses: false
-SpacesInAngles:  false
-SpaceInEmptyParentheses: false
-SpacesInCStyleCastParentheses: false
-SpacesInContainerLiterals: true
-SpaceBeforeAssignmentOperators: true
-ContinuationIndentWidth: 4
-CommentPragmas:  '^ IWYU pragma:'
-ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
-SpaceBeforeParens: ControlStatements
-DisableFormat:   false
+BasedOnStyle:  Google
 ...