pinsDebug for 644/1284 & USB646/1286 families

added conditional compilation for PWMs 1C & 3C

add Teensyduino compatibility

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changes per review - minor formatting changes

1) remove non-printable character at the end of line 687

2) split a really long comment into two lines

3) got rid of some trailing spaces

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Made pinsDebug_Teensyduino.h the same between this PR and PR 5668 which
is for a re-written pinsDebug.h file.

The changes were:
1) added copyright @ GNU license header
2) a blank line crept in.