Remove empty newlines in #include blocks.

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

src/.clang-format

@@ -50,6 +50,8 @@ IncludeCategories:
     Priority:        1
   - Regex:           '^\<(boost|catch|dynarmic|glad|inih|nihstro)/'
     Priority:        3
+  - Regex:           '^\<(SDL|SoundTouch|Q)'
+    Priority:        3
   - Regex:           '^\<'
     Priority:        2
 IndentCaseLabels: false