Add stuff for cmake find_package

- Add build* to gitignore
- Fix year in license file
- other changes are result of clang-format

include/pd/ui7/layout.hpp

@@ -34,7 +34,7 @@ SOFTWARE.
 
 namespace PD {
 namespace UI7 {
-  class Context;
+class Context;
 class PD_API Layout {
  public:
   Layout(const ID& id, IO::Ref io) : ID(id) {