cpu/board: added ADC driver for stm32f0discovery

- added ADC implementation for the stm32f0 cpu
- added ADC pin/device configuration for stm32f0discovery board
cpu/board: added ADC driver for stm32f4discovery
cpu/cortex-mX_common: fixed type issues

- added explicit cast for stack pointer
- fixed printf type inconsistency
converting tabs to spaces in boards (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
'''find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;'''
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
converting tabs to spaces in cpu (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
```find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;```
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
converting tabs to spaces in dist (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
```find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;```
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
converting tabs to spaces in drivers (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
```find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;```
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
converting tabs to spaces in sys (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
```find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;```
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
converting tabs to spaces in tests (#1439)

This PR converts tabs to white spaces.
The statement I used for the conversion:
```find . -name "*.[ch]" -exec zsh -c 'expand -t 4 "$0" > /tmp/e && mv /tmp/e "$0"' {} \;```
Afterwards, I had a quick overview of the converted files to prevent odd indentation.
Merge pull request #1470 from haukepetersen/add_stm32f4_adc

cpu/board: added ADC driver for stm32f4discovery
Merge pull request #1512 from cgundogan/remove_tabs_boards

converting tabs to spaces in boards (#1439)
Merge pull request #1514 from cgundogan/remove_tabs_cpu

converting tabs to spaces in cpu (#1439)
Merge pull request #1505 from haukepetersen/add_stm32f0_adc

cpu/board: added ADC driver for stm32f0discovery
Merge pull request #1517 from cgundogan/remove_tabs_sys

converting tabs to spaces in sys (#1439)
Merge pull request #1509 from haukepetersen/fix_cortexmcommon_cppcheck

cpu/cortex-mX_common: fixed type issues in thread_arch
Merge pull request #1516 from cgundogan/remove_tabs_drivers

converting tabs to spaces in drivers (#1439)
Merge pull request #1515 from cgundogan/remove_tabs_dist

converting tabs to spaces in dist (#1439)
Merge pull request #1518 from cgundogan/remove_tabs_tests

converting tabs to spaces in tests (#1439)