Add "streaming" syntax support to Print class

I wrote a couple of lines of helper code to allow for easy printing. If anyone is interested, I could incorporate it in `Stream.h` and open a pull request.

Usage:

```cpp
int a {9};
int b {10};
Serial << "You have " << a << " out of " << b << " retries left.\n";
// Prints: "You have 9 out of 10 retries left."
Serial << makePair(1.2, 4) << ' ' << makePair(12, BIN) << '\n';
// Prints: "1.2000 1100"
```

Start by reading Stream.h and the Print class, then compare the requested << usage examples with the existing printing API. Done means the shown string, integer, character, and makePair examples are supported and produce the documented output.

Written by the indexing model from the issue text.