Add .travis.yml for Travis CI

.travis.yml

+language: c
+
+# Install dependencies
+before_install:
+  - sudo apt-get -qq update
+  - sudo apt-get install -y autoconf automake
+  - sudo apt-get install -y libxml2 libxslt1-dev libssl-dev libcurl4-openssl-dev
+  - sudo apt-get install -y libogg-dev libspeex-dev libtheora-dev libvorbis-dev
+
+# Build commands
+script: ./autogen.sh && ./configure && make
+
+# Compilers to build with
+compiler:
+  - clang
+  - gcc