renaming script_test_data as qiime_test_data

this will show up as a separate package under site-packages when installed with setup.py, so it's important that the name is descriptive"
removed files necessary for stand-alone repository
modified setup.py to install qiime_test_data
modified strategy for finding qiime_test_data repo

now that it's in qiime, we don't need it's location in qiime_config anymore