rename documentation/*.h -> .dox

documentation/mainpage.dox

@@ -0,0 +1,28 @@
+#ifndef MAINPAGE_H
+#define MAINPAGE_H
+/**
+@mainpage pvAccess C++ docs
+
+- [Download](https://sourceforge.net/projects/epics-pvdata/files/)
+- @htmlonly <a href="modules.html">API components</a> @endhtmlonly
+- @ref pvarelease_notes
+- API documentation
+ - @ref pvac page
+ - @ref pvas page
+ - @ref providers page
+ - @ref pvtools
+
+@section main_examples API usage Examples
+
+- Simple synchronous (blocking) examples
+ - @ref examples_miniget
+ - @ref examples_miniput
+ - @ref examples_minimonitor
+- More complete callback based examples
+ - @ref examples_getme
+ - @ref examples_putme
+ - @ref examples_monitorme
+ - @ref examples_mailbox
+*/
+
+#endif /* MAINPAGE_H */