Case sensitivity: MemDiscountLimit should have capital M
BUGFIX: syntax error on batch cut/paste queries
Safely Renaming a Column in custdata, pt 2
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Fannie Cleanup
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Remove unnecessary references to MemDiscountLimit.
Omitting it from INSERTs is safe because it has
a default value. Letting a model class handle
INSERTs is better because only the model will
need revisions if MemDiscountLimit is removed
entirely.

Also legacy and store-specific revisions. Code
here just assumed custdata.ChargeLimit exists.
Unnecessary references to MemDiscountLimit are
again removed so the column itself can be
eliminated in the future.
Safely Renaming a Column in custdata, pt 3
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Lane Code Cleanup
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Easy. The lane only access the limit value
via the memchargebalance view which has
already been updated. So this just removes
stale references.

PrehLib and the gui-modules all issue the same
query to get a record from custdata. The query
requests the MemDiscountLimit column but never
does anything with it. No reason to have the
column name there.

CoreState looks up the limit value in its
crash recovery function but does not do anything
useful with it. Again no reason to have the column
name there.
Override default styles so text prints black reliably.