core/debug: don't disable usart receiver

Otherwise reception on USART doesn't work and hence Ethersex
doesn't handle ECMDs via serial line.

This was changed by commit 1273083d59e45e1aa6ca9bbb22a19004bc9fcf48,
supposedly accidentaly.
fixed syntax error
Added own hardware
Fix bug bsbport not compileing without polling
reformating and some typos
Merge pull request #338 from AnDann/master

New module for BoilerSystemBus
fix syntax error in 1wire's ecmd code
closes #340
fix compiler warnings
fix missing register for atmega168p/328p and rfm12_fs20
Merge pull request #343 from AnDann/fix_missing_reg

fix missing register for atmega168p/328p and rfm12_fs20
add cie1931 8 to 12 bit luminance correction
add fading to target value from current with adjust speed
dirty hack in clock.c with no solution so far
bugfix in periodic.c
cie1931 table added
changed clock processing for better clock accuracy with pwm enabled
bugfix in header led´s should start with off
changed fade counter
removed PWM_LED from clock.c
fixed bug in fading routine caused fading to do only one step
fix compiler warning in pwm.c
fix pin in use, if hw_spi in use with custom cs pin and hardware cs pin is used as arbitrary pin it will not compile
Merge branch 'pwm_cie1931_fade' of https://github.com/AnDann/ethersex into pwm_cie1931_fade