Added Travis test script

This builds Openlibm on the Travis build host (x86) and also
cross-compiles to ARM.

Note: the tests currently fail on ARM, as noted in
JuliaMath#18

.travis.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+set -eux
+
+case "$TARGET" in
+host)
+	uname -a
+	export LOADER=
+	make ;;
+arm32)
+	sudo apt-get -y install gcc-4.6-arm-linux-gnueabihf qemu binfmt-support
+	make CC="arm-linux-gnueabihf-gcc-4.6"
+	export LD_LIBRARY_PATH=/usr/arm-linux-gnueabihf/lib
+	export LOADER=/usr/arm-linux-gnueabihf/lib/ld-linux-armhf.so.3
+	;;
+*)
+	echo 'Unknown TARGET!'
+	exit 1
+	;;
+esac
+
+$LOADER ./test/test-double
+$LOADER ./test/test-float

.travis.yml

@@ -0,0 +1,5 @@
+language: c
+script: ./.travis.sh
+env:
+- TARGET=host
+- TARGET=arm32