Add "unsafe fixes" runtime option

In this case it fixes occurences of invalid multi-value separators.
DSpace uses "||" to separate multiple values in one field, but our
editors sometimes give us files with mistakes like "|". We can fix
these to be correct multi-value separators if we are sure that the
metadata is not actually using "|" for some legitimate purpose.

tests/test_fix.py

@@ -23,3 +23,11 @@ def test_fix_excessive_whitespace():
     value = 'Alan  Orth'
 
     assert fix.whitespace(value) == 'Alan Orth'
+
+
+def test_fix_invalid_separators():
+    '''Test fixing invalid multi-value separators.'''
+
+    value = 'Alan|Orth'
+
+    assert fix.separators(value) == 'Alan||Orth'