engine/var: Filters no longer support regular expressions.  RNS-1065 RNS-1067
engine/var.c: Fix bug in recent removal of filter regexps.
engine/core_tfns.c: String transformations now properly handle empty strings.  RNS-1069
util/bytestr.c: ib_bytestr_alias_mem() now properly handles empty strings. RNS-1069
predicate/standard_template.cpp: Fix bug in ref expansion. RNS-1069
predicate/tests/tc_predicate.rb: Add test of template transformation. RNS-1069
predicate/merge_graph.cpp: Fix corner case in remote_tree(). RNS-1069
predicate/merge_graph: Replace naive learning of changed ancestors to a knitting process that will properly merge ancestors that are now identical to other nodes. RNS-1069
predicate/merge_graph: Refactor some common code out into an update_root() function.
predicate/ibmod_predicate.cpp: Make assert valid always on.
engine/core_tfns.c: Fix urlDecode on empty strings.
transformations: Transformations that operate on byte strings should not error on zero-length byte strings.
util/string_trim.c: Fix bug with only whitespace input.  RNS-1072
predicate/standard_list: Fix bug where cat wasn't finishing properly. RNS-1073
predicate/eval: GraphEvalState::eval() now returns void rather than Value.  This eliminates tricky bugs related to node forwarding by requiring all value queries to go through GraphEvalState::value().  RNS-1073
predicate/reference: Fix incorrect documentation on truthy values.
transformations: Adding unit tests for zero-length strings and fixing two exposed bugs where the length was not checked first when it should have been.
normalizeSqlPg, normalizeSqli: Adding unit tests for zero-length strings.
etc: Update example configuration file for 0.10.x.