Adding support for other message sets (#40)

* MavMessage::parse now maps results instead of unwrapping them, so there's no panic

* also compile ardupilotmega.xml

* rustfmt

* updated connections to be generic

* it builds! support for ardupilotmega messages added, still need parsing + tests

* it all works! it also no longer compiles on rust 1.40.0 for some reason, but it works fine on rust stable 1.41.1 so i don't think it's a big deal

* documented features, added build binder

* fixed Cargo.toml

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* added ability to patch mavlink schemas

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* removed extraneous println statements

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* mavlink should no longer rebuild every single time

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* fixed extra_crc

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* fixed travis ci

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* fixed travis ci again?

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* fixed merge mistake

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* rustfmt + fix merge mistake part 2

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* updated readme and crate documentation

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* tests are now feature-gated + added common feature

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* feature-gated the rest of the tests + added common as a default feature

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* build with all features on docs.rs

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>

* fixed imports in tests

Signed-off-by: Ibiyemi Abiodun <ibiyemi@intulon.com>