MB-10447 Add a wrapper script for running unit tests

The current CouchDB unit tests uses perl utility program prove
for executing and parsing etap test output. A shell script is
used to set the erlang environment variables required by the
tests. On windows platform, build system cannot run shell script
as well as perl scripts.

Added a python script that can perform parsing of etap test output
and also set necessary environment variables. CMake test framework
can make use of this script to implement cmake tests for CouchDB on
all platforms.

The script can be executed as follows:
./runtest.py -p $COUCHDB_PATH -m $COUCHDB_PATH/src/couch_set_view,$COUCHDB_PATH/src/couch_set_view/test -t test/02-old-index-cleanup.t

Change-Id: Ic8d90815901466322c32e6578fb79081b6c69cad
Reviewed-on: http://review.couchbase.org/34466
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>