core: sched: thread: optimize thread status field usage

see PR #716 for discussion
sys: update ps to reflect thread status variable changes
add oonf_api pkg
always build and initialize hwtimer

Eliminates special treatment of the hwtimer module and makes it a
mandatory part of the kernel.
removed duplicate inISR prototype
added documentation of configuring the right debug stack size for uart0 module
native: removed unreachable code
test: fix bloom filter test
Merge pull request #779 from mehlis/native-unreachable-code

native: removed unreachable code
simplified sched_switch

sched_switch can check ISR itself.
build id shell command only for config module

closes #777
ifdef shell _heap_handler for corresponding module
Add a mechanism for handling fatal errors (and reboots)
Implement the crash-handling/reboot mechanism for MSP430 MCUs
Implemented crash-handling mechanism for 'native' platform
Implemented the crash-handling/reboot mechanism for ARM-based MCUs
LPC1768 implementation of 'core_panic()'
copied from 'arm_common', for make-related reasons...
Merge pull request #781 from LudwigOrtmann/sc_id

build id shell command only for config module
Merge pull request #776 from OlegHahm/uart0_stack_documentation

added documentation of configuring the right debug stack size for uart0 module
Merge pull request #714 from OlegHahm/hwtimer_integration

core: always build and initialize hwtimer