Add esutil package

The complication is that esutil ships with its own `ups/esutil.table` file.
It also overwrites the shipped version in `setup.py`.

We want to use our own custom table file.  To do this I did the following:
* made an override to `prep` to link the LSST version into place after the package
is unpacked.
* added a patch that removes the parts of `setup.py` that rewrite the file.

Note that we still need to include a link to the LSST table file in the repo, even though
it is overwritten, to setup the environment initially.

README.rst

@@ -0,0 +1,6 @@
+esutil
+******
+
+This is a package provided by Erin Sheldon (esheldon on github).
+There are lots of nice utilities.  In particular, the HTM python
+bindings are used in reference catalog sharding.

patches/setup.patch

@@ -0,0 +1,26 @@
+--- a/setup.py	2015-11-10 07:15:20.000000000 -0800
++++ b/setup_new.py	2016-03-30 17:55:22.000000000 -0700
+@@ -13,23 +13,6 @@
+ pylib_install_subdir = main_libdir.replace(distutils.sysconfig.PREFIX+os.sep,'')
+ pylib_install_subdir = pylib_install_subdir.replace('dist-packages','site-packages')
+
+-if not os.path.exists('ups'):
+-    os.mkdir('ups')
+-tablefile=open('ups/esutil.table','w')
+-tab="""
+-# The default version of this file will be overwritten on setup to include
+-# paths determined from the python version.  This is useful to have in place
+-# though so that dependencies can be checked *before* installation.  Currently
+-# there are no required dependencies, so this is somewhat moot.
+-
+-setupOptional("python")
+-setupOptional("cjson")
+-envPrepend(PYTHONPATH,${PRODUCT_DIR}/%s)
+-""" % pylib_install_subdir 
+-tablefile.write(tab)
+-tablefile.close()
+-
+-
+
+ # can we build recfile?
+ packages = ['esutil']

ups/esutil.table

@@ -0,0 +1 @@
+esutil.table.lsst

ups/esutil.table.lsst

@@ -0,0 +1,3 @@
+setupRequired(python)
+setupRequired(numpy)
+envPrepend(PYTHONPATH, ${PRODUCT_DIR}/lib/python)

ups/eupspkg.cfg.sh

@@ -0,0 +1,15 @@
+TAP_PACKAGE=1
+
+prep()
+{
+        default_prep
+
+        # Move the LSST copy of esutil.table over the one that ships with esutil
+        UPS_DIR="ups"
+        LSST_TABLE="esutil.table.lsst"
+        ESUTIL_TABLE="esutil.table"
+
+        cd ${UPS_DIR}
+        [ -f ${ESUTIL_TABLE} ] && rm ${ESUTIL_TABLE}
+        ln -s ${LSST_TABLE} ${ESUTIL_TABLE}
+}