implemented log rotate on SIGUSR2
added logs for logRotate error cases
added success log for rotation file
added documentation + UT for log rotate
changes after code review
updated UT depending on code review changes
fixed rain to work with node 0.10
refactored file appender
added documentation in file descriptor ass well
platform appenders were created 2 times
updated documentation
made rotateFile optional and renamed day to days
small doc changes
merged topic-log-rotate