dev-python/pymediainfo: bump to 2.1.3, add doc

[sbraz]

@idella or @monsieurp
There is one warning during the doc build, I've fixed it upstream.

--- pymediainfo-2.1.2.ebuild    2016-05-01 23:32:09.713745645 +0200
+++ pymediainfo-2.1.3.ebuild    2016-05-04 12:46:55.369674125 +0200
@@ -15,17 +15,27 @@
 LICENSE="MIT"
 SLOT="0"
 KEYWORDS="~amd64 ~x86"
-IUSE="test"
+IUSE="doc test"

 RDEPEND="media-libs/libmediainfo"
 DEPEND="
        dev-python/setuptools[${PYTHON_USEDEP}]
+       doc? ( dev-python/sphinx[${PYTHON_USEDEP}] )
        test? (
                ${RDEPEND}
                dev-python/nose[${PYTHON_USEDEP}]
        )
 "

+python_compile_all() {
+       use doc && esetup.py build_sphinx
+}
+
 python_test() {
        nosetests tests || die "tests failed with ${EPYTHON}"
 }
+
+python_install_all() {
+       use doc && local HTML_DOCS=( docs/_build/html/. )
+       distutils-r1_python_install_all
+}