Split out predicates and settings.

- cdsl.predicates defines classes for describing predicates.
- cdsl.settings defines classes for describing settings.
- base.settings defines shared settings.

lib/cretonne/meta/isa/riscv/settings.py

@@ -2,9 +2,9 @@
 RISC-V settings.
 """
 from __future__ import absolute_import
-from cretonne import SettingGroup, BoolSetting
-from cretonne.predicates import And
-import cretonne.settings as shared
+from cdsl.settings import SettingGroup, BoolSetting
+from cdsl.predicates import And
+import base.settings as shared
 from .defs import isa
 
 isa.settings = SettingGroup('riscv', parent=shared.group)