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/l1/pwr.c

@@ -1,3 +1,20 @@
+/** @defgroup pwr-file PWR
+
+@ingroup STM32L1xx
+
+@brief <b>libopencm3 STM32L1xx Power Control</b>
+
+@version 1.0.0
+
+@author @htmlonly &copy; @endhtmlonly 2012 Karl Palsson <karlp@tweak.net.au>
+
+@date 4 March 2013
+
+This library supports the power control system for the
+STM32L1 series of ARM Cortex Microcontrollers by ST Microelectronics.
+
+LGPL License Terms @ref lgpl_license
+*/
 /*
  * This file is part of the libopencm3 project.
  *