RIOT-OS/RIOT — pull request #1867 by haukepetersen (2014-10-23 16:29:11+00:00)
Title: cpu/stm32f0: optimizations to UART driver

Optimized the UART driver for less memory usage. See numbers for `tests/periph_uart_int`:

before:

```
text	data	bss	dec	hex
19464	116	5548	25128	6228
```

and after:

```
text data bss dec hex
18544 116 5548 24208 5e90
```