This mainly moves the STM32 timers' code to the common area.

F2 and F4 have a common section to deal with the options register (TIM2 and TIM5 only)
L1 has been made common with timer_common_all as its options register has very different settings to F2/F4. Code is in the L1/timer.c L1/timer.h files

Note that F3 and F05 timers should fit into this scheme, with F3 having additional features.

Bundled with this is L1/pwr.h to change a documentation setting
Also all the Doxyfiles have added "ENABLE_PREPROCESSING = NO" to fix a problem introduced by commit 118.

lib/stm32/f2/timer.c

@@ -0,0 +1,40 @@
+/* This file is used for documentation purposes. It does not need
+to be compiled. All source code is in the common area.
+If there is any device specific code required it can be included here,
+in which case this file must be added to the compile list. */
+
+/** @defgroup timer_file Timers
+
+@ingroup STM32F2xx
+
+@brief <b>libopencm3 STM32F2xx Timers</b>
+
+@version 1.0.0
+
+@date 18 August 2012
+
+*/
+
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Edward Cheeseman <evbuilder@users.sourceforge.org>
+ * Copyright (C) 2011 Stephen Caudle <scaudle@doceme.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/timer.h>
+#include <libopencm3/stm32/common/timer_common_f24.h>
+