Pass tydescs to parametric fns, along with (dummy, presently) retptr when needed. Can call simple parametric fn now.

Change single-ident expr_ident to greedy/fat multi-ident expr_path, to handle the module-path/value-indexing distinction.

Modify translation of obj methods to accept an initial recursive-self-typed (in the LLVM sense) obj argument.

Mop up cases of s/copy/take/, remove 'binding' terminology, whitespace police, and make obj/fn structural.

rustc: Use the passed-in tydescs for take and drop glue in parametric fns. Also fix a level-of-indirection problem with tydesc params.

rustc: Build tydescs for types, and make all take and drop operations go through the tydescs for simplicity (LLVM inlines them).