The new code is smaller and faster and perhaps also easier to understand

fix 2 bugs introduced in PR #35

Test case:
https://gist.github.com/vgheo/f34ac7afd6447b3f1fc4

Iterate over all defined protocols in `handleInterrupt`

Travis integration + Readme changes

Fixed a dumb error (duplicate lines)

So far, while decoding the timings, the `handleInterrupt`routine only
iterated over protocols 1-3 before failing.

This small change will iterate over *all* protocols that have been
defined.

Tweak initial high signal of protocol 3

This resolves issue #32 (with a recent Globaltronics GT-FSI-07), and also is necessary
for compatibility with my Brennenstuhl RCS 2044.

Adds compilation support for Raspberry Pi

Resolves #8

Protocols as structs

Various minor improvements and cleanups

This results in much smaller and more efficient machine code.

It should not affect correctness, either: Indeed, the delay value
is computed from dividing an int by another int, so it fits into an int.
The delayTolerance is a fraction of that int, so it also fits.
Intermediate results like delay * pro.zero.high are ints because they
are equal to
 timings[0] * pro.zero.high / pro.syncFactor.low
but syncfactor.low is always larger (at least in all current protocols)
than any other high/low value.

Also get rid of the dummy protocol (which was only there to
make the proto array indices match the protocol numbers.
Now they are off by one, but this saves 8 bytes of valuable storage.

The resulting code is actually simpler, and more powerful at the
same time

This clarifies the code. It also reduces the code size
by another 1000 bytes or so.