fix brainfuck for new tree-il, and add tests

* test-suite/Makefile.am:
* test-suite/tests/brainfuck.test: Add a brainfuck test.

* module/system/base/compile.scm: Also export read-and-compile.

* module/language/tree-il/spec.scm (join): Fix the joiner in the
  0-expression case.

* module/language/tree-il/primitives.scm (+): Recognize (+ x -1) as 1-.

* module/language/brainfuck/parse.scm (read-brainfuck): Return EOF if we
  actually received EOF, and there were no expressions read.

* module/language/brainfuck/compile-tree-il.scm (compile-body): Fix the
  compiler for the new format of "lambda" in tree-il.

module/system/base/compile.scm

@@ -28,7 +28,10 @@
   #:use-module (ice-9 receive)
   #:export (syntax-error 
             *current-language*
-            compiled-file-name compile-file compile-and-load
+            compiled-file-name
+            compile-file
+            compile-and-load
+            read-and-compile
             compile
             decompile)
   #:export-syntax (call-with-compile-error-catch))