docs/deprecation.rst,include/xapian/queryparser.h,
queryparser/queryparser.cc,queryparser/queryparser.lemony,
queryparser/queryparser_internal.h,tests/queryparsertest.cc:
Allow setting the expansion limits and types for wildcards
and partial terms in the QueryParser independently. Partial
terms now default to the 100 most frequent matching terms.
Deprecate set_max_wildcard_expansion() in favour of new
set_max_expansion() method which can set expansion limits
for partial terms too. Completes #608.