Repair to documentation (most documented files)

to remove errors, duplications and inconsistencies.
File lib/stm32/f1/pwr.c - all code removed as it duplicates that in common/pwr_common.c
Remaining changes do not affect code. Compiles OK.
TODO efm32 has no code so generates no modules
TODO F2 needs pwr.c
TODO L1 needs dma.h and dma.c

lib/stm32/common/gpio_common_all.c

@@ -1,4 +1,8 @@
-/** @addtogroup gpio_file */
+/** @addtogroup gpio_file
+
+@author @htmlonly &copy; @endhtmlonly 2009 Uwe Hermann <uwe@hermann-uwe.de>
+
+*/
 
 /*
  * This file is part of the libopencm3 project.