commit: abi: add convenience methods to look up AbiSuite files

Decided to break my own rules and stray into XP territory.

I have added two methods to XAP_App (and XAP_CocoaApp):
findAbiSuiteLibFile(...)
findAbiSuiteAppFile(...)
which look for a file first in the user's dir then, if not found, the
system AbiSuite lib-dir.

In the CocoaAbi case I have made the system AbiSuite dir
"/Library/Application Support/AbiSuite", and if the file is not found
there then the AbiWord.app bundle's Resources dir is checked.

I'm hoping this doesn't break stuff. I'm only testing on one
platform... Patch attached for your perusal.

o add new virtual convenience methods to XAP_App to search for files
such
   as templates, ispell dictionaries, profiles, etc.
o hard-wire system-level AbiSuite in CocoaAbi as
   "/Library/Application Support/AbiSuite"
o extend new App methods in CocoaApp to search also in bundle Resources
CVS:
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CVS: Enter Log. Lines beginning with `CVS:' are removed automatically
CVS:
CVS: Committing in .
CVS:
CVS: Modified Files:
CVS: src/af/xap/cocoa/xap_CocoaApp.h
CVS: src/af/xap/cocoa/xap_CocoaApp.mm src/af/xap/xp/xap_App.cpp
CVS: src/af/xap/xp/xap_App.h src/other/spell/xp/ispell_checker.cpp
CVS: src/other/spell/xp/ispell_checker.h
CVS: src/text/ptbl/xp/pd_Document.cpp
CVS: src/wp/ap/cocoa/ap_CocoaApp.mm src/wp/ap/xp/ap_Prefs.cpp
CVS:
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Regards, Frank