minor readme updates
[git-p4: depot-paths = "//src/flay/dev/": change = 8328]
! Added --fuzzy (ie copy, paste, & modify) duplication detection.
+ Added Sexp#modified, #modified=, and #modified?.
+ Added Sexp#initalize_copy to propagate file/line/modified info.
+ Wrapped Sexp#[] to propagate file/line/modified info.
+ Added Sexp#+.
+ Added Sexp#split_at(n). (Something I've wanted in Array for ages).
+ Added Sexp#code_index to specify where *code starts in some sexps.
+ Added Sexp#has_code?.
+ Added Sexp#split_code.

Some of these should probably be pushed up to sexp_processor... but
I'll test drive them here for now.

[git-p4: depot-paths = "//src/flay/dev/": change = 8329]