refactor(change_detection): add change_detection library file

modules/change_detection/src/change_detection.js

@@ -0,0 +1,7 @@
+export {ChangeDetectionError, ChangeDetector} from './change_detector';
+export {AST, ASTWithSource} from './parser/ast';
+export {Lexer} from './parser/lexer';
+export {Parser} from './parser/parser';
+export {ProtoRecordRange, RecordRange, ChangeDispatcher} from './record_range';
+export {ProtoRecord, Record} from './record';
+export {ContextWithVariableBindings} from './parser/context_with_variable_bindings';