min() and max() definitions cause incompatibilities with standard min() and max()

[ASL07]

Hi,

The definition of min() and max() on Arduino.h causes conflicts and force other libraries to use undefine these macros if they want to use the standard ones.

I wonder if this is ok or maybe it should be modified

[prototypicalpro]

I've made a pull request to address this issue: #399. Unfortunately it's been rather quiet.