errno -> process._errno
allow interfaceIndex to be "really big"

apparently mDNSShared/dns_sd.h uses

#define kDNSServiceInterfaceIndexLocalOnly ((uint32_t)-1)
errno for 0.8.x and 0.10.x

as suggested by @ronkorving
Merge pull request #1 from Wizcorp/errno-fixes

Errno fixes by @mrose17