Integrated VCard Line into PropertyBuilder structure.
PropertyBuilder now has a method to set its values from a VCardLine.
Each implementation copies/converts its values and performs appropriate
error-checking.
Added/updated testcases.
Also added a method/fields for handling the group component of VCardLine
as well as making sure that it is output correctly by __toString().
VCardLine no longer unescapes its property values.
Removing cslashes early can lead to parsing failure in
StructuredPropertyBuilder, etc., because escaped separators can end up being
significant. We want to leave separators protected until all parsing of
the property values is complete.
Added reports director to ignore list.