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/recipes.py

@@ -11,7 +11,7 @@ instruction formats described in the reference:
 from __future__ import absolute_import
 from cretonne import EncRecipe
 from cretonne.formats import Binary, BinaryImm
-from cretonne.predicates import IsSignedInt
+from cdsl.predicates import IsSignedInt
 
 # The low 7 bits of a RISC-V instruction is the base opcode. All 32-bit
 # instructions have 11 as the two low bits, with bits 6:2 determining the base