Use standard library style members of wxArrayString (and wxString) ...

... which will make it easier to change the types of those containers to
std::vectors of other string-like classes

for wxString,

IsEmpty => empty
Clear => clear
Alloc => reserve

for wxArrayString,

Count => size
GetCount => size
IsEmpty => empty
Add => push_back
Clear => clear
Empty => clear
Sort => std::sort (only with default comparator)
SetCount => resize
Last => back
Item => operator []
Alloc => reserve

src/Sequence.cpp

@@ -993,7 +993,7 @@ void Sequence::HandleXMLEndTag(const wxChar *tag)
       SeqBlock &block = mBlock[b];
       if (block.start != numSamples) {
          wxString sFileAndExtension = block.f->GetFileName().name.GetFullName();
-         if (sFileAndExtension.IsEmpty())
+         if (sFileAndExtension.empty())
             sFileAndExtension = wxT("(replaced with silence)");
          else
             sFileAndExtension = wxT("\"") + sFileAndExtension + wxT("\"");