Fixed small typo

The element LclInstrm was used as LclInstr, which is incorrect according to pain.001.001.03.xsd
Added 'COR1' as allowed code for localinstrument

COR1 is allowed in some cases, for instance for the EPC:

 - COR1 is used to cater for optional shorter time cycle (D-1) for a Core direct
debit
Merge pull request #6 from NanneHuiges/master

Fixed a small typo for the element "LocalInstrument"