Use #{`}#, #{,}# and #{,@}# as the quasiquote, unquote and
unquote-splicing operators, respectively. Previously they were named
escaping.
* module/language/elisp/compile-tree-il.scm (unquote?): Change "\," to
"#{,}#".
(unquote-splicing): Change "\,@" to "#{,@}#".
(#{compile-`}#): Rename from #{compile-\`}#.
* module/language/elisp/runtime/function-slot.scm: Import #{compile-`}#
instead of #{compile-\`}#, and re-export as #{`}# instead of as
#{\`}#.
* module/language/elisp/parser.scm (quotation-symbols):
* test-suite/tests/elisp-compiler.test ("Eval", "Quotation"):
* test-suite/tests/elisp-reader.test ("Parser"): Change "\`", "\,", and
"\,@" to "#{`}#", "#{,}#" and "#{,@}#", respectively.
* module/language/elisp/parser.scm: New parser file.
* module/language/elisp/lexer.scm: Fix lexer/1 and add unquote-splicing support.
* module/language/elisp/spec.scm: Use new elisp-reader.
* module/language/elisp/README: Document we've got a reader now.
* test-suite/tests/elisp-reader.test: Test the parser.
* module/language/elisp/lexer.scm: New lexer file.
* test-suite/Makefile.am: Register elisp-reader.test as new test.
* test-suite/tests/elisp-reader.test: New test-case.
