Fix compiler warning due to incorrect array new syntax

This fixes the following warning:

    healpy/src/_healpy_sph_transform_lib.cc:49:39: warning: ISO C++ does
    not support variable-length array types [-Wvla]
Use Python 3 compatible except syntax
Remove unnecessary Python 2-style print statement
First step toward Python 3 compatibility

`python setup.py build` and `import healpy` now work in Python 3.
Fix possible segfault if PyUFunc_FromFuncAndData returns NULL

The function PyModule_AddObject checks if the value you are passing it
is non-NULL.
Fix testbuild.sh interpreter

There is no such thing as `/bin/env`; it's in `/usr/bin/env`.
All unit tests but one pass on Python 3.2+

The exception is this one:

    =================================== FAILURES ===================================
    ____________ TestPixelFunc.test_ang2pix_nest_outofrange_doesntcrash ____________

    self = <healpy.test.test_pixelfunc.TestPixelFunc testMethod=test_ang2pix_nest_outofrange_doesntcrash>

        def test_ang2pix_nest_outofrange_doesntcrash(self):
            # ensure nside = 1 << 30 is incorrectly calcualted,
            # because Healpy_Base2 works upto 1<<29.
            # Healpy_Base2 shall not crash the test suite
            id = ang2pix(1<<30, self.theta0, self.phi0, nest=True)
            theta1, phi1 = pix2ang(1<<30, id, nest=True)
            self.assertFalse(np.all(np.isfinite(theta1)))
    >       self.assertFalse(np.all(np.isfinite(phi1)))
    E       AssertionError: True is not false

    test/test_pixelfunc.py:64: AssertionError
    ===================== 1 failed, 78 passed in 10.03 seconds =====================

but I think that this itself is a bug, because Healpy should support full 64-bit HEALPix indexes up to and including `nside=1<<30`.
Document Python 3+ support in README
Merge pull request #186 from lpsinger/python3

Add support for Python 3.2, 3.3, 3.4
Test multiple Python versions with Travis

Based on <http://conda.pydata.org/docs/travis.html>. Test with both
Anaconda and native Ubuntu Python interpreters.
Don't use C99 designated initializers

It causes some build failures in Travis CI.
Wrap travis_retry around pip commands

Sometimes there are network glitches which cause `pip` to fail with the
message `Connection reset by peer`. If we wrap `pip` commands with
`travis_retry`, these commands will be tried up to three times before
causing a build failure.

See <http://docs.travis-ci.com/user/build-timeouts/>.
Skip Python 3.4 if not using Anaconda

The Ubuntu package used by Travis seems to use different default
compiler flags.
Disable internal cfitsio builds for Python 2.6 and 3.3

These configurations are almost redundant, and they are some of the
slower configurations.
Merge pull request #188 from lpsinger/multi_python_travis

Test multiple Python versions with Travis: 2.6, 2.7, 3.3, 3.4