Fix deprecated examples extension ( *.pde → *.ino)

[neomilium]

2 commits in this PR to clean the code:

• Rename examples that use obsolete Arduino extension (ie. *.pde) to current one *.ino

• Remove any #include that involves a Cpp file, header suffice

[ackPeng]

@neomilium Thank you very much for your PR, but on my host, if I don't have #include<xxx.cpp>, I will get an error of undefined reference to `PN532_HSU::PN532_HSU

[neomilium]

@ackPeng Which development environment do you use? PlatformIO, Ardunio IDE, other?

[ackPeng]

@neomilium I am using Arduino IDE

[neomilium]

I'll try with this IDE.

[neomilium]

OK, I see why it causes this under Arduino IDE.
To fix it, we will need to rework the way user include the library, so its a bigger PR.
I will remove this commit and keep the examples extension fix.

[ackPeng]

@neomilium Thank you very much for your contribution