Bug 9593: improve parsing of prices from staged files

Bug 9593: improve parsing of prices from staged files

Initial bug :
When there's a round price with no decimals after it,
or when the symbol is after the digits, the price is not captured
by regular expression in MungeMarcPrice routine and the variable
is not initialized.

Enhancement :
The MungeMarcPrice routine had been widely modified.
It's still possible to priority pick the active currency but
unlike the previous mechanism that worked only for prices preceded
by the currency sign, it's now valid wherever the symbol is situated.
As symbol you may enter a pure currency sign as well as a string
including it like '$US'. Moreover, an 'isocode' column had been
added in currency table (editable in the staffo interface from
Administration/Currencies and exchange rates). So the active
currency can be picked either through its symbol or through its iso
code.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes all tests, especially t/db_dependent/MungeMarcPrice.t
Checked currencies can be added, edited and deleted.
Notes: new ISO code field is mandatory.
       Sample sql files need to be updated (bug 12146)

Signed-off-by: Galen Charlton <gmc@esilibrary.com>