pypi.bbclass: bring in from meta-python

The pypi.bbclass has usefullness in many meta layers, not
just meta-python. Add it to oe-core for the benefit of
everyone.

Documentation strings for PYPI_PACKAGE, PYPI_PACKAGE_EXT and
PYPI_SRC_URI added to meta/conf/documentation.conf

(From OE-Core rev: c350812523017f113f63e0b863fd526b4d6331b9)

Signed-off-by: Tim Orling <timothy.t.orling@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

(From Yocto rev: 7d950b99bdb0f3c91eb060d31711243a7d3366fc)

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: Ia3a8b4d492cd50851fd95204710ac6c779ec7437
diff --git a/import-layers/yocto-poky/meta/conf/documentation.conf b/import-layers/yocto-poky/meta/conf/documentation.conf
index a55e283..081e726 100644
--- a/import-layers/yocto-poky/meta/conf/documentation.conf
+++ b/import-layers/yocto-poky/meta/conf/documentation.conf
@@ -338,6 +338,9 @@
 PROVIDES[doc] = "A list of aliases that a recipe also provides. These aliases are useful for satisfying dependencies of other recipes during the build as specified by DEPENDS."
 PRSERV_HOST[doc] = "The network based PR service host and port."
 PV[doc] = "The version of the recipe. The version is normally extracted from the recipe filename."
+PYPI_PACKAGE[doc] = "The python package name to use for fetching from pypi. Default is parsed from the recipe name, but can be overridden if upstream name is different than recipe name."
+PYPI_PACKAGE_EXT[doc] = "The archive file extension to use for fetching from pypi. Default is tar.gz, but can be overridden if upstream uses a different compression scheme."
+PYPI_SRC_URI[doc] = "The URI to use to fetch from pypi, default uses pythonhosted.org and is constructed from PYPI_PACKAGE, PYPI_PACKAGE_EXT and PV."
 
 #Q