* pmsleep refactor
* Shortened swtmr disabled message
* Added swtimer debug module option to user_modules.h.
* Added comments to user_config.h.
* Fixed error in documentation for node.sleep()
* remove blank sntp.c that got added in during rebase onto dev(6218b92)
* Added #ifdefs around SWTIMER_REG_CB to prevent inclusion of disabled
code
dnc40085