getter func should followe go convention: http://golang.org/doc/effective_go.html#Getters
support ProcessId
Merge pull request #1 from xiangli-cmu/master
add name field to fix #1
add error string
switch license to Apache v2 to fix issue #2
Minor fixes
Merge https://github.com/ccding/go-logging

Conflicts:
	logging/fields.go