[Kst] Plugin Error Codes

[George Staikos]

I received no feedback about plugin error codes, so I defined some myself.  -1 
is a generic error, -2 is input error (the inputs are invalid for the 
plugin), and -3 is a memory error.  0 on success as usual.  The rest are 
reserved for future use.  Errors are dumped to KstDebug.

-- 
George Staikos
KDE Developer				http://www.kde.org/
Staikos Computing Services Inc.		http://www.staikos.net/