leo/plugins/spellpyx.txt is both source controlled and customized

A file that is both source controlled and customized by the user is inconvenient for both novices and experts. Such a file is inconvenient for a novice running Linux because the novice probably does not have write access to leo/plugins/spellpyx.txt. Such a file is inconvenient for an expert who uses Bazaar to pull the latest revision because pulling may require merging the user's customizations with Leo-Editor maintainer changes.

Hence, it is undesirable that file leo/plugins/spellpyx.txt is both source controlled and customized by the user.

Example of user customization:
Copy file leo/plugins/spellpyx.txt to a file, say base.txt.
Run the Leo-Editor spell checker on text containing a word that spell flags as misspelled.
Click the "Add" button in the spell pane.
Now diff leo/plugins/spellpyx.txt and base.txt.
Note that the word you "added" is at the end of leo/plugins/spellpyx.txt.
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Suggested fix:

Allow two spell word lists: leo/plugins/spellpyx.txt and ~/.leo/spellpyx.txt

These lists are "additive". That is, any word in either list is accepted.

Make the spell "Add" always add to ~/.leo/spellpyx.txt, creating it if necessary.
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Forum thread:
https://groups.google.com/forum/#!topic/leo-editor/HLrqAudBgBw
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My test system:
Xubuntu 12.04
Leo Log Window
Leo 4.11 devel, build 5752, 2013-04-27 12:44:31
Python 2.7.3, qt version 4.8.1
linux2
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I believe the Leo-Editor spell checker has worked this way for a very long time.