[eval2] Update portable and CCL-specific code.
[eval2] Move implementation specifics out of eval2.lisp.
[eval2] Various fixes.
Make COMPILE of MINIMALLY-COMPILED-FUNCTIONs recur through the instance fun.
[eval2] Implement COMPILER-LET.
[eval2] More small fixes.
[eval2] Rewrite %TAGBODY using COMPILER-LET.
[eval2] Small fixes.
[eval2] Fix CONTEXT->NATIVE-ENVIRONMENT on Clozure CL.
[eval2] Fix ANSI compliance bugs in the portable version.
[eval2] Add functions LOAD2, EVAL2 (primarily for testing purposes).
[eval2] Improve ANSI compliance.
[eval2] Fix a copy'n'paste error.
[eval2] Further improve ANSI conformance.
[eval2] Don't generate large numbers of distinct special variables.
[eval2] Formatting.
[eval2] Improve ANSI compliance.