Added IDC validation of anySimpleType attribute values; anyway the IDC key
* xmlschemas.c: Added IDC validation of anySimpleType attribute values; anyway the IDC key comparison is restricted to anySimpleType <--> string based types. For other types we would possibly need the canonical lexical representation of them; this sounds not performant, since we would need to build such a representation each time we want to compare against anySimpleType. TODO: think about buffering the canonical values somewhere. Fixed error reports for default attributes to work without a node being specified. This all and the enabling of IDC validation fixes bug #165346 (reported by Benoit Gr?goire - could not read his last name correctly from bugzilla).