define more const variables for default configuration values
improved the configuration extension to support configuration change saving
support dynamic server instance loading
added one test case to cover adding server in the runtime
Add KeyStorageFlags property in CertificateConfig

Add KeyStorageFlags property in CertificateConfig to used by the
CertificateManager to instantiate the X509Certificate2
added the support of keyStorageFlags for the security configuration node
fixed an exception that the socket session has been closed when sending data
updated version in the nuspec
fixed some compatible issues of .NET 3.5 projects
added nuget package jobs in the build tasks
fixed a bug that subscribing an event by mistake, the original purpose was to unsubscribe it
upgraded version to 1.6.3
fixed the log4net missing issue for the QuickStart project
fixed a warning in the QuickStart project
fixed an exception when collect a server's status but it has been stopped
improved the build task file
fixed a bug that can cause an exception in case of sending data when the connection dropped already
upgraded the version of nuget package to 1.6.3
fixed a bug about status data collecting which could cause the application crash
exposed the appsession instantiating as protected virtual  method