Adde methods to se if static IP addresses were configured, and what those addresses are

[jonasbjurel]

To be able to find out if the network with static addresses or with DHCP following methods are proposed:

//check if static network configuration is set
bool          isStaticIp(void);

//provides static host ip address provided method isStaticIp() returns true
void          getStaticIp(IPAddress* staticIp);

//provides static gateway ip address provided method isStaticIp() returns true
void          getStaticGw(IPAddress* staticGw);

//provides static network mask provided method isStaticIp() returns true
void          getStaticSn(IPAddress* staticSn);

//provides static DNS ip address provided method isStaticIp() returns true
void          getStaticDns(IPAddress* staticDns);