Update Travis Configuration (#273)

Various improvements to the Travis CI script:
* Add channel order builds to releases - now building AETR, TAER, and RETA
* Add PPM builds for each channel order with no inversion and PPM banks set to 5
* Log config diff for each build (diff output folded to keep the log readable)
* Colorify the "Building" lines to make parsing the log easier
* Export .bin files instead of .hex files for the AVR modules
* Add Multi.txt to the release files

buildroot/bin/opt_replace

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+SED=$(which gsed || which sed)
+
+eval "${SED} -i 's/#define \b${1}\b$/#define ${2}/g' Multiprotocol/_Config.h"