add SafeLogger to swallow exceptions

 - this gives consumers an option to use Perfadilly without worry of it causing failures in consuming code
move all InsternalStatsEnabled to Config
log errors as stats in SafeLogger
add IPerfLoggerAppender.IsEnabled

 - update PerfLogger and AggregatedPerfLogggerAppender to only call enabled appenders
add AggregatedPerfLoggerAppender.RefreshAppenders

 - allows refresh the appenders at runtime
reference MSpec & Moq & supporting libraries
remove Machine.Fakes.Moq package
replace PerfLoggerSettings w/ Config.KeyPattern

 - and update get perf logger to take logger name instead of type
add comments to IPerfLogger
update Config comments
rename to NullPerfLoggerAppender
remove unused test packages
replace ObjectPrinter with nuget package for ObjectPrinter
remove unused log4net proj
prep Perfadilly for nuget publishing
appender cleanup: minor refactors, comments, etc
load ObjectPrinter from nuget
rename _nullLogger to NullLoggerInstance
enable nuget package restore
add package.bat & publish.bat for nuget