Some spi modifications and DEBUGHTTP proposing

[ska-la]

for newMods:

1. It's proposed to use DEBUGHTTP in TcpStack.h(cpp) files to facilitate tracking HTTP session's behaviour (from start to end) and distinguishing a debug messages from inner (hardware) events.
2. Amendments in enc28typedef.h file are proposed for a code compatibility with other than ATmega328p uCs. It's tested on Mega2560 board (well working). Atmega328/168 use SS = 10, Atmega1280/2560 - SS = 53, Atmega32u4 - SS = 17... (look through a pins_arduino.h files in IDE). SPI_MISO, SPI_MOSI, SPI_SCK aren't used in the library at all.
3. SPI.begin() is removed from TcpStack.cpp . Please, look at https://github.com/ska-la/arduino_patches/wiki/SD_hard_atmega.patch

Thanks.