hal: k20 - flash config section addition
Add thumbv7[e]m-linux-eabi target specs
hd44780u: Fix dereferences
Merge pull request #220 from bgamari/target-spec

Added rustc target specs
Merge pull request #221 from bgamari/misc-fixes

hd44780u: Fix dereferences
Issues from extension trait changes
Update target-specs for executable files
Modify travis build to use GitHub tarballs

Instead of cloning and checkout, just grab the appropriate tarball
from GitHub.
Merge pull request #222 from bharrisau/nightly100

Issues from extension trait changes
Merge pull request #223 from bharrisau/target-specs2

Update target-specs for executable files
Merge pull request #224 from bharrisau/travis2

Modify travis build to use GitHub tarballs
stm32l1 - basics of USART registers
stm32l1 - Added all control registers, implemented the initialization.
stm32l1 - improved the current frequency computation.
stm32l1 - implemented most of the clock configuration.
stm32l1 - MCO clock support
stm32l1 - improved clock configuration, completed HSI and MSI parts
stm32l1 - implemented RCC->CSR registers, bus frequency getters.
stm32l1 - enabled use of USART in the app_blink
stm32l1 - moved usart test code into a separate app