Code Cleanup

- Renamed parse.cpp -> valid.cpp to reflect its new role of housing
  all the validation routines that don't belong to objects.
- Split report.cpp into report.cpp and custom.cpp.

src/Makefile.am

@@ -3,8 +3,8 @@ 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 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                           \
+               import.cpp interactive.cpp valid.cpp recur.cpp report.cpp      \
+               custom.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 Task.h TDB2.h Table.h Timer.h color.h    \