Implemented backendconfig.
Moved metrics stuff to metricsmanager.cs.
ConfigManager.cs work.
StackConfig,WebServerConfig, StatisticsConfig, LogConfig will now set defaults if it can read from config json.
Fixed a tiny bug with LogTarget where it was throwing an exception incorrectly for non-file based targets.
added exception handler for nancy trying to run on a well-known port without being root
Removed coin-config caches, as most of time we won't need to load a coin config more then once.
Coin-configs are now correctly valided and if one fails the validation referring pool config will be also skipped.
Merge pull request #309 from raistlinthewiz/develop

config reader improvements