Add Travis support

Author: apoelstra

.travis.yml

@@ -0,0 +1,11 @@
+
+before_install:
+  - sudo add-apt-repository --yes ppa:hansjorg/rust
+  - sudo add-apt-repository --yes ppa:cmrx64/cargo
+  - sudo apt-get update -qq
+install:
+  - sudo apt-get install -qq rust-nightly cargo
+script:
+  - cargo build
+  - cargo test
+