title: Add custom header to Xcode project to hold related imports in one place
body: <p>I've realised that that I have like 4 or 5 related .h files that I have to import at few places. It seems reasonable to create a one .h file, add all imports to it and then only import one new file instead of 5.
  First of all, is this a common practice? Or is there a nicer way?</p>
  
  <p>In Xcode, when I try to do so using File -> New -> File... -> Source -> Header File the newly created header holds this:</p>
  
  <pre><code>#ifndef MyProject_MyProjetCommonHeader_h
  #define MyProject_MyProjetCommonHeader_h
  
  #endif
  </code></pre>
  
  <p>Not sure why these preprocessor commands needed. And it doesn't recognise (autocomplete) any headers when I try to use #import. Am I doing it wrong?</p>