transformer, ast, syntax: Remove deprecated modules.

These modules were concerned with converting Python parse tree into AST
in Python versions 1.5.x - early 2.x. Since then, the "ast" module, with
elaborated API, was promoted to the top-level module in Python stdlib.
Previous changes in this repository were concerned with porting other
modules (symbols, pycodegen, etc.) from those historical modules to the
modern "ast" module.

Thus, these modules are unused and removed to clean up the package and ease
maintenance. Note that the topic of parsing Python source code into AST
using pure-Python module(s) is definitely interesting, but better be pursued
via separate project(s). This project has well-defined scope - compile a
standard Python AST into bytecode and code objects.

Author: pfalcon

compiler/__init__.py

@@ -1,15 +1,8 @@
-"""Package for parsing and compiling Python source code
+"""Package for compiling Python source code
 
 There are several functions defined at the top level that are imported
 from modules contained in the package.
 
-parse(buf, mode="exec") -> AST
-    Converts a string containing Python source code to an abstract
-    syntax tree (AST).  The AST is defined in compiler.ast.
-
-parseFile(path) -> AST
-    The same as parse(open(path))
-
 walk(ast, visitor, verbose=None)
     Does a pre-order walk over the ast using the visitor instance.
     See compiler.visitor for details.
@@ -21,11 +14,5 @@
     Generates a .pyc file by compiling filename.
 """
 
-import warnings
-
-warnings.warn("The compiler package is deprecated and removed in Python 3.x.",
-              DeprecationWarning, stacklevel=2)
-
-from compiler.transformer import parse, parseFile
 from compiler.visitor import walk
 from compiler.pycodegen import compile, compileFile

compiler/ast.py

@@ -7,7 +7,7 @@
 from io import StringIO
 
 import ast
-from compiler import parse, walk, syntax
+from compiler import walk
 from compiler import pyassem, misc, future, symbols
 from compiler.consts import SC_LOCAL, SC_GLOBAL_IMPLICIT, SC_GLOBAL_EXPLICIT, \
      SC_FREE, SC_CELL