lib/codegen-meta moved into lib/codegen. (#423)

* lib/codegen-meta moved into lib/codegen.

* Renamed codegen-meta and existing meta.

lib/codegen/meta-python/isa/arm32/__init__.py

@@ -0,0 +1,15 @@
+"""
+ARM 32-bit Architecture
+-----------------------
+
+This target ISA generates code for ARMv7 and ARMv8 CPUs in 32-bit mode
+(AArch32). We support both ARM and Thumb2 instruction encodings.
+"""
+
+from __future__ import absolute_import
+from . import defs
+from . import settings, registers  # noqa
+from cdsl.isa import TargetISA  # noqa
+
+# Re-export the primary target ISA definition.
+ISA = defs.ISA.finish()  # type: TargetISA