pw_tokenizer: Python package

Add the pw_tokenizer Python package, which is used to manage token
databases and decode tokenized strings. pw_tokenizer can be used from
other Python code or from the command line. Three command line utilities
are provided:

  - database.py: Manage tokenized string databases.
  - detokenize.py: Decode and detokenize strings.
  - elf_reader.py: Read data from ELF files by section or address.

Change-Id: I87b19a8f8433a34a254560fc72e5522a74d5a02d
diff --git a/pw_tokenizer/BUILD b/pw_tokenizer/BUILD
index 59883fc..7fe7aa1 100644
--- a/pw_tokenizer/BUILD
+++ b/pw_tokenizer/BUILD
@@ -82,6 +82,20 @@
     ],
 )
 
+# Executable for generating a test ELF file for elf_reader_test.py. A host
+# version of this binary is checked in for use in elf_reader_test.py.
+cc_binary(
+    name = "elf_reader_test_binary",
+    srcs = [
+        "py/elf_reader_test_binary.c",
+    ],
+    linkopts = ["-Wl,--unresolved-symbols=ignore-all"],  # main is not defined
+    deps = [
+        ":pw_tokenizer",
+        "//pw_varint",
+    ],
+)
+
 pw_cc_test(
     name = "argument_types_test",
     srcs = [