feat(directive): Add ng-attr-* interpolation support
feat(directives): Add support for contenteditable with ng-model
chore(warnings): Fix static warnings in parser generator and compile perf test.
chore(lexer): Lex a.b.c as three individual tokens
feat(mock): support for JSON in HttpBackend

Closes #236
fix(scope): honor $skipAutoDigest on non-root scopes

Close #391