Update the pin layout table and consolidate the RPi readme files.

 - Changes in the pin layout table to describe how to connect the NRF24L01 pins to different boards
 - Remove duplicate readme information in the RPi readme file and point to the default RPi/RF24/readme.md file.
Select a standard pin layout for the examples.

Choose a standard pin layout for all the examples based on the pin connection table in the readme files.
Different pin layout in the example files could lead to not working examples.
Fix wrong pin layout
RPi B+ Update to BCM2835 V1.37

http://www.airspayce.com/mikem/bcm2835/bcm2835-1.37.tar.gz

- Merge with latest BCM2835 driver changes
- Should allow full support for RPi B+ but is untested
RPi B+ Update to BCM2835 V1.37

http://www.airspayce.com/mikem/bcm2835/bcm2835-1.37.tar.gz

- Merge with latest BCM2835 driver changes
- Should allow full support for RPi B+ but is untested

... not sure why the .h file was left out the first time...
Teensy Support

Per a tip from Andrew A. this should be the final nail in the coffin of
issue #7
Add RPi B+ info to main examples and readme
#24 Enable UART as 2ndary SPI BUS

Uses the SPI_UART library at https://github.com/TMRh20/Sketches
#24 Add softSPI supp, fix SPI_UART

- Added softSPI support for https://github.com/greiman/DigitalIO library
- Updated SPI_UART code to allow use at the same time as the SPI library
#25 Fix CRC status, revert to default SPI lib

- Revert SPI to default lib by default. Configure via RF24_config.h #24
- Corrected CRC status reporting per https://github.com/evorios by
checking AA register
#24 Fix: SoftSPI or UartSPI working with std SPI

Fix compile errors when trying to use any of the three libraries
together - should allow softspi and uartspi to play nicely with the std
SPI library now
#24 lol Fix: Spelling and ; on std spi define
Fix broken ATTiny support in updates branch
Merge remote-tracking branch 'origin/Updates'