Script for building wheels with manylinux docker

Manylinux provides docker images for building wheels on CentOS 5
(https://github.com/pypa/manylinux)

Add script for building Essentia wheels using these images
- Install newer yasm and cmake to build dependencies (CentOS 5 is
  in stone age)
- Patch provided python-config scripts to avoid explicit linking to
  libpython (pypa/manylinux#87)
- Build dependencies and wheels

travis/build_wheels.sh

@@ -0,0 +1,80 @@
+#!/bin/bash
+
+set -e -x
+
+# yasm on CentOS 5 is too old, install a newer version
+wget http://www.tortall.net/projects/yasm/releases/yasm-1.3.0.tar.gz
+tar -xvf yasm-1.3.0.tar.gz
+cd yasm-1.3.0
+./configure
+make
+make install
+cd ..
+
+# cmake is also too old, taglib requires CMake 2.8.0
+# use curl; there's a SSL certificate error with wget
+curl -L --remote-name http://www.cmake.org/files/v2.8/cmake-2.8.10.2.tar.gz
+tar -xvf cmake-2.8.10.2.tar.gz
+cd cmake-2.8.10.2
+./configure --prefix=/usr/local/cmake-2.8.10.2
+make
+make install
+PATH=/usr/local/cmake-2.8.10.2/bin:$PATH
+cd ..
+
+function lex_pyver {
+     # Echoes Python version string padded with zeros
+     # Thus:
+     # 3.2.1 -> 003002001
+     # 3     -> 003000000
+     echo $1 | awk -F "." '{printf "%03d%03d%03d", $1, $2, $3}'
+}
+
+
+for PYBIN in /opt/python/*/bin; do
+
+# Patch python-config scripts (https://github.com/pypa/manylinux/pull/87)
+# Remove -lpython from the python-config script.
+
+    if [ -e ${PYBIN}/python3 ]; then
+        ln -sf python3 ${PYBIN}/python
+        ln -sf python3-config ${PYBIN}/python-config
+    fi
+
+    py_ver="$(${PYBIN}/python -c 'import platform; print(platform.python_version())')"
+
+    if [ $(lex_pyver $py_ver) -lt $(lex_pyver 3.4) ]; then
+        echo "Patching python 2"
+        sed -i "s/'-lpython' *+ *pyver\( *+ *sys.abiflags\)\?/''/" $(readlink -e ${PYBIN}/python-config)
+    else
+        echo "Patching python 3"
+        sed -i 's/-lpython${VERSION}${ABIFLAGS}//' $(readlink -e ${PYBIN}/python-config)
+    fi
+done
+
+
+# Build static 3rdparty dependencies
+/io/packaging/build_3rdparty_static_debian.sh
+
+# Compile wheels
+for PYBIN in /opt/python/*/bin; do
+# use older version of numpy for backwards compatibility of its C API
+    "${PYBIN}/pip" install numpy==1.8.2
+    ESSENTIA_WHEEL_SKIP_3RDPARTY=1 "${PYBIN}/pip" wheel /io/ -w wheelhouse/ -v
+done
+
+# Bundle external shared libraries into the wheels
+for whl in wheelhouse/*.whl; do
+# Do not run auditwheel for six package because of a bug
+# https://github.com/pypa/python-manylinux-demo/issues/7
+    if [[ "$whl" != wheelhouse/six* ]];
+    then
+        auditwheel repair "$whl" -w /io/wheelhouse/
+    fi
+done
+
+# Install packages and test
+for PYBIN in /opt/python/*/bin/; do
+    "${PYBIN}/pip" install essentia --no-index -f /io/wheelhouse
+    (cd "$HOME"; ${PYBIN}/python -c 'import essentia; import essentia.standard; import essentia.streaming')
+done