build: search headers in all source directories

* removed paths in include directives
* changed cmake to provide necessary header search paths
* changed name of version.h to productVersion.h due to name conflict

src/lib/project/SourceGroup.h

@@ -5,9 +5,9 @@
 #include <set>
 #include <vector>
 
-#include "settings/LanguageType.h"
-#include "settings/SourceGroupStatusType.h"
-#include "settings/SourceGroupType.h"
+#include "LanguageType.h"
+#include "SourceGroupStatusType.h"
+#include "SourceGroupType.h"
 
 class IndexerCommand;
 class IndexerCommandProvider;