Minor changes to Communication Examples

Added a note to the included Processing sketches about replacing
println(Serial.list()) with Serial.printArray() if using Processing 2.1
or later
Update readme.txt
Update and rename readme.txt to README.mkdn
Rename README.mkdn to README.md
Updated Listfiles SD example

Changed SS pin to 4 for consistency with other examples
Merge pull request #1836 from KonradIT/master

Use markdown lang in the readme.
WiFi Shield examples: added the firmware version check
If 2 libs have same .h file, use the lib with same dir name
Merge pull request #1853 from PaulStoffregen/master

If 2 libs have same .h file, use the lib with same dir name
Fixed issue #1478, #1599, #1709, motors being opposite, updated turning algorithm
Revert "Changed pins definition in variants from constants to #defines."

This reverts commit 7fcba37acfd11313640b3f5d5c813d63d2f59999.
Merge branch 'master' of github.com:X-Y/Arduino into X-Y-master
Added some friendly messages for Arduino Robot include errors on old sketches

After merging #1859, old sketches that uses Robot_Control library must include
Wire.h and SPI.h to work properly.
Added license for Arduino.h, binary.h and main.cpp (master branch)

See #1847 and #1117
Added license for Client, IPAddressm and Server (master branch)

See #1847 and #1117
Update README.md

Decapitalised secondary headings and linked the *Credits* section
Merge pull request #1867 from felixphew/patch-2

Update README.md
Local (user installed) libraries have priority over system libraries

See #1853
Removed unused code, fixed indentation.
Corrected repeated 'less' in checkName's message