Enhancements - info report

- Implemented info report.
- Removed odd Subst and Sequence objects from Task - are they just
  vestigial limbs, or did I add them for a good reason?  They are
  gone now.
- Added Filter::applySequence to replace old filterSequence.
- Removed obsolete report.cpp filter function.

src/main.h

@@ -90,8 +90,6 @@ std::string handleEdit ();
 // report.cpp
 std::string shortUsage ();
 std::string longUsage ();
-void filterSequence (std::vector<T>&, T&);
-void filter (std::vector<T>&, T&);
 std::string handleInfo ();
 std::string handleReportSummary ();
 std::string handleReportNext ();