First bits of STM32L1 support: memory model, blink app, logic placeholders
stm32l1 - improved pin types
stm32l1 - implemented/refactored the peripheral_clock module
stm32l1 - fixed OTYPER offset
stm32l1 - implemented RCC/FLASH/PWR registers. Fixed GPIO registers.
stm32l1 - implemented the timer.
stm32l1 - fixed the stack pointer
stm32l1 - migrated init and peripheral_clock to the new ioregs
stm32l1 - migrated pin and timer modules to the new ioregs
stm32l1 - removed the clock code that is not yet ported, fixed the copyright.
stm32l1 - minor styling fixes revealed by code review
stm32l1 - reimplemented Pin structure, improved timer registers.
stm32l1 - added basic of the system clock
Merge pull request #193 from kvark/stm32l1

Added basic hal implementation for STM32L1
Do not strip exception handlers; bloats binaries.

This is a temporary solution to allow exceptions
happening while waiting for some resolution at
https://github.com/rust-lang/rust/issues/17886
Replace GPIO with Gpio

Begin to bring things into complicance with the Rust style guide.
Merge pull request #208 from bgamari/style

Replace GPIO with Gpio
Add TI Tiva C controller support.

Currently supported:
 - GPIO
 - System clock configuration
 - UART TX with polling
 - Timer support with polling
 - Platform tree support