Detect clang flags

Hi, I have tested this locally, and it's working for me  by picking up my .clang_complete for the project and using those compile flags to let the linter show meaningful hits. I *think* I've done the appropriate thing with code styles, but I am new to coffeescript, node and atom, so I welcome feedback.
You can use `@filePath` instead of `atom.workspace.getActiveEditor().getPath()`.