Add some more comments, especially to the linereader
Rename the linereader module file more appropriately
Simplify the interface to the linereader
Fix memory issue
Annotate environment.c
Remove unused `ty' field from env_t struct and related routines
Annotate the header
Move `evlist' and `makelist' to util.c
Move TCO debugging stuff to a separate file
GUI: remove some debugging stuff