clang format: preliminary support

Add a .clang-format example file. Might need minor tuning. If people doesn't like the syntax

Add a basic script to validate current change is compliant with clang-format
* on master it will test last 20 commits
* on branch it will test all commits of the branch

Idea is to plug it into travis (might require clang 3.8). Everything is blacklisted. Use "ALL" parameters
to test all standard directories.

.clang-format

@@ -0,0 +1,77 @@
+---
+Language:        Cpp
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: true
+AlignConsecutiveDeclarations: true
+AlignEscapedNewlinesLeft: false
+AlignOperands:   true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: true
+AllowShortFunctionsOnASingleLine: All
+AllowShortIfStatementsOnASingleLine: true
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: true
+BinPackParameters: true
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Linux
+BreakBeforeTernaryOperators: false
+BreakConstructorInitializersBeforeComma: true
+ColumnLimit:     0
+CommentPragmas:  '^ (IWYU pragma:|NOLINT)'
+ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ForEachMacros:   []
+IncludeCategories:
+  - Regex:           '^"(stdafx|PrecompiledHeader)'
+    Priority:        -2
+  - Regex:           '^".*Common'
+    Priority:        -1
+  - Regex:           '^<'
+    Priority:        1
+  - Regex:           '^"'
+    Priority:        2
+IndentCaseLabels: true
+IndentWidth:     4
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: true
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 3
+NamespaceIndentation: None
+ObjCBlockIndentWidth: 2
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: true
+PenaltyBreakBeforeFirstCallParameter: 19
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 60
+PointerAlignment: Left
+ReflowComments:  true
+SortIncludes:    false
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Cpp11
+TabWidth:        4
+UseTab:          Never
+...