start refactoring based on enc28j60 internal memory
refactor UIPEthernet to use Enc28J60Network memory management (compiles, not running stable yet)
EchoServer.ino (tcp-example) working as long size of data submitted at once fits in a single package.
fix tcp-checksum
Fixed pointer to periodic timer.  Added mega detection for SPI config.
Renamed clock and timer libraries and methods to resolve naming
conflicts with other libraries.
Merge pull request #5 from brunnels/dev

Fixed pointer to periodic timer.  Added mega detection for SPI config.
chksums refactored, read tcp and udp payload directly from enc28j60 memory
Merge branch 'dev' of https://github.com/ntruchsess/arduino_uip into dev
fix udp checksum
Merge pull request #7 from ntruchsess/dev

Major refactoring to use enc28j60 internal memory whenever possible