rust: update and merge eval-ast

Remove unneeded intermediate executable files.
Remove Cargo.lock from version control system.
Update dependency versions.
Update Dockerfile (converge to update-some-dockerfiles branch).
Apply changes suggested by rustfmt and clippy, or enforced by rustc.
Remove several unneeded clone().
Merge eval and eval-ast, remove quasiquoteexpand and macroexpand.
Report more errors during startup.

Makefile.impls

@@ -176,7 +176,7 @@ rexx_STEP_TO_PROG =          impls/rexx/$($(1)).rexxpp
 rpython_STEP_TO_PROG =       impls/rpython/$($(1))
 ruby_STEP_TO_PROG =          impls/ruby/$($(1)).rb
 ruby.2_STEP_TO_PROG =        impls/ruby.2/$($(1)).rb
-rust_STEP_TO_PROG =          impls/rust/$($(1))
+rust_STEP_TO_PROG =          impls/rust/target/release/$($(1))
 scala_STEP_TO_PROG =         impls/scala/target/scala-2.11/classes/$($(1)).class
 scheme_STEP_TO_PROG =        $(scheme_STEP_TO_PROG_$(scheme_MODE))
 skew_STEP_TO_PROG =          impls/skew/$($(1)).js