- Changed the return type for vtimer_init,vtimer_set_msg and vtimer_remove.
- Current return value is not used anywhere and has no meaning attached to it.
- Fix for #1533
- Removed tests which checked for vtimer_set_msg being set.
- Done doxygen adaption for corresponding vtimer functions.
Currently, when using vtimer_set_msg the corresponding msg_t is filled
with the MSG_TIMER ("12345") type.
This approach makes it difficult to differentiate between incoming
messages via vtimer_set_msg.
In this PR I introduce another parameter for the vtimer_set_msg
function to specify a custom msg_t type.
Instead of using differing integer types use kernel_pid_t for process
identifier. This type is introduced in a new header file to avoid
circular dependencies.
