Plugin sometimes fails on XML declaration

[lwilli]

User reported not being able to view WSDL in Sublime Text build 4143. User also reported similar issue in Sublime 3.

Errors in log:

[WARNING ClickableWsdl]: Expected a namespaced name, but got '?xml'.
[WARNING ClickableWsdl]: Expected a namespaced name, but got '?xml'.
[ERROR ClickableWsdl]: Cannot find the closing tag for element 'None:None' (422, 460)
[ERROR ClickableWsdl]: Cannot find the closing tag for element 'None:None' (478, 516)
Traceback (most recent call last):
  File "/private/var/folders/xl/_2vsmw0n4092d0qmsp70w4_m0000gq/T/AppTranslocation/C059A12E-99F8-455C-9D52-C70A6FBD67FE/d/Sublime Text.app/Contents/MacOS/Lib/python33/sublime_plugin.py", line 1494, in run_
    return self.run(edit)
  File "/Users/username/Library/Application Support/Sublime Text/Installed Packages/Clickable WSDL.sublime-package/clickable_wsdl.py", line 332, in run
  File "/Users/username/Library/Application Support/Sublime Text/Installed Packages/Clickable WSDL.sublime-package/clickable_wsdl.py", line 269, in find_definition_region_for_clickable
  File "/Users/username/Library/Application Support/Sublime Text/Installed Packages/Clickable WSDL.sublime-package/clickable_wsdl.py", line 270, in <listcomp>
  File "/Users/username/Library/Application Support/Sublime Text/Installed Packages/Clickable WSDL.sublime-package/clickable_wsdl.py", line 350, in contains_region
  File "/private/var/folders/xl/_2vsmw0n4092d0qmsp70w4_m0000gq/T/AppTranslocation/C059A12E-99F8-455C-9D52-C70A6FBD67FE/d/Sublime Text.app/Contents/MacOS/Lib/python33/sublime.py", line 993, in cover
    a = min(self.begin(), rhs.begin())
AttributeError: 'NoneType' object has no attribute 'begin'