Merge pull request #2 from CAM-Gerlach/fix-xml-parsing

Fix XML parsing, add a basic CLI and resolve a number of minor code quality, best practice and style issues

diff --cc pull.py
index 48f014d6b653ac59be9163a9a97c6e32c354651b,f67d2e739e655ef4abc9fd83525db7a04a8ebd3c..5472219e583a09c206ce0f5bf7632cec882f844d
--- 1/pull.py
--- 2/pull.py
+++ b/pull.py
@@@ -150,12 -152,16 +152,16 @@@ IDENTIFIERS = 
      'FDLv1.1': {'spdx': ['GFDL-1.1-or-later', 'GFDL-1.1-only', 'GFDL-1.1']},
      'FDLv1.2': {'spdx': ['GFDL-1.2-or-later', 'GFDL-1.2-only', 'GFDL-1.2']},
      'FDLv1.3': {'spdx': ['GFDL-1.3-or-later', 'GFDL-1.3-only', 'GFDL-1.3']},
 -    'FreeBSD': {'spdx': ['BSD-2-Clause-FreeBSD']},
 +    'FreeBSD': {'spdx': ['BSD-2-Clause-FreeBSD', 'BSD-2-Clause', 'BSD-2-Clause-NetBSD']},
      'freetype': {'spdx': ['FTL']},
      'GNUAllPermissive': {'spdx': ['FSFAP']},
-     'GNUGPLv3': {'spdx': ['GPL-3.0-or-later', 'GPL-3.0-only', 'GPL-3.0', 'GPL-3.0+']},
+     'GNUGPLv3': {
+         'spdx': ['GPL-3.0-or-later', 'GPL-3.0-only', 'GPL-3.0', 'GPL-3.0+']
+     },
      'gnuplot': {'spdx': ['gnuplot']},
-     'GPLv2': {'spdx': ['GPL-2.0-or-later', 'GPL-2.0-only', 'GPL-2.0', 'GPL-2.0+']},
+     'GPLv2': {
+         'spdx': ['GPL-2.0-or-later', 'GPL-2.0-only', 'GPL-2.0', 'GPL-2.0+']
+     },
      'HPND': {'spdx': ['HPND']},
      'IBMPL': {'spdx': ['IPL-1.0']},
      'iMatix': {'spdx': ['iMatix']},