Fix types in transceiver.c
Merge pull request #631 from authmillenon/fix-transceiver-types

Fix types in transceiver.c
model uart dependency on posix
remove trailing newlines
remove superfluous uart USEMODULEs from examples
remove superfluous uart USEMODULEs from test
update test_shell/ReadMe.txt
Merge pull request #634 from LudwigOrtmann/uart_posix_dep

uart related cleanup