Code Cleanup

- Renamed T2.h -> Task.h, T2.cpp -> Task.cpp.  This permanently avoids
  the problem where g++ on OpenBSD 4.5 fails because of the T class,
  which probably conflicts with C++ templates.  Who knows.

src/Makefile.am

@@ -1,12 +1,12 @@
 bin_PROGRAMS = task
 task_SOURCES = Att.cpp Cmd.cpp Config.cpp Context.cpp Date.cpp Duration.cpp   \
                Filter.cpp Grid.cpp Keymap.cpp Location.cpp Nibbler.cpp        \
-               Record.cpp Sequence.cpp StringTable.cpp Subst.cpp T2.cpp       \
+               Record.cpp Sequence.cpp StringTable.cpp Subst.cpp Task.cpp     \
                TDB2.cpp Table.cpp Timer.cpp color.cpp command.cpp edit.cpp    \
                import.cpp interactive.cpp parse.cpp recur.cpp report.cpp      \
                rules.cpp main.cpp text.cpp util.cpp                           \
                Att.h Cmd.h Config.h Context.h Date.h Duration.h Filter.h      \
                Grid.h Keymap.h Location.h Nibbler.h Record.h Sequence.h       \
-               StringTable.h Subst.h T2.h TDB2.h Table.h Timer.h color.h      \
+               StringTable.h Subst.h Task.h TDB2.h Table.h Timer.h color.h    \
                i18n.h main.h text.h util.h                                    \
                T.cpp T.h TDB.cpp TDB.h