New plugin bootreasonlogger

This logs shutdown and startup reasons to file
/var/lib/dsme/systemboot.log  (we have also symlink in /var/log/systemboot.log)
File looks like this

20131205_151751 Startup:  pwr_on_status=pwr_on_by_USB
20131205_151854 Shutdown: User Power Key
20131205_151935 Startup:  pwr_on_status=pwr_on_by_pwr_key
20131205_152235 Shutdown: User Power Key
20131205_152517 Startup:  pwr_on_status=pwr_on_by_RTC
20131205_152627 Shutdown: SW shutdown request
20131205_152653 Startup:  pwr_on_status=pwr_on_by_pwr_key
20131205_152803 Shutdown: Reason Unknown
20131205_152830 Startup:  pwr_on_status=pwr_on_by_SW_reboot
20131209_114220 Shutdown: User Power Key
20131209_114319 Startup:  pwr_on_status=pwr_on_by_pwr_key
20131209_114421 Received: battery  empty
20131209_114447 Shutdown: Battery empty
20131209_114510 Startup:  pwr_on_status=pwr_on_by_USB
20131209_114810 Received: battery  empty
20131209_114841 Startup:  pwr_on_status=pwr_on_by_RTC
20131209_114849 Shutdown: SW shutdown request
20131209_114939 Startup:  pwr_on_status=pwr_on_by_pwr_key
[root@localhost ~]#