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
Merge pull request #1879 from h2g2guy/master

Corrected repeated 'less' in checkName's message
Added copyright license for WiFi shield library

See #1117