Rename the entity_ref module to 'entity'.

This is in preparation for moving a number of data structures into
sub-modules of the 'entity' module:

- EntityList
- EntityMap
- SparseMap

lib/frontend/src/frontend.rs

@@ -7,7 +7,7 @@ use cretonne::ir::function::DisplayFunction;
 use cretonne::isa::TargetIsa;
 use ssa::{SSABuilder, SideEffects, Block};
 use cretonne::entity_map::{EntityMap, PrimaryEntityData};
-use cretonne::entity_ref::EntityRef;
+use cretonne::entity::EntityRef;
 use std::hash::Hash;
 
 /// Permanent structure used for translating into Cretonne IL.
@@ -571,7 +571,7 @@ impl<'a, Variable> FunctionBuilder<'a, Variable>
 #[cfg(test)]
 mod tests {
 
-    use cretonne::entity_ref::EntityRef;
+    use cretonne::entity::EntityRef;
     use cretonne::ir::{FunctionName, Function, CallConv, Signature, ArgumentType, InstBuilder};
     use cretonne::ir::types::*;
     use frontend::{ILBuilder, FunctionBuilder};

lib/frontend/src/lib.rs

@@ -35,7 +35,7 @@
 //! extern crate cretonne;
 //! extern crate cton_frontend;
 //!
-//! use cretonne::entity_ref::EntityRef;
+//! use cretonne::entity::EntityRef;
 //! use cretonne::ir::{FunctionName, CallConv, Function, Signature, ArgumentType, InstBuilder};
 //! use cretonne::ir::types::*;
 //! use cton_frontend::{ILBuilder, FunctionBuilder};

lib/frontend/src/ssa.rs

@@ -10,7 +10,7 @@ use cretonne::ir::{Ebb, Value, Inst, Type, DataFlowGraph, JumpTables, Layout, Cu
 use cretonne::ir::instructions::BranchInfo;
 use std::hash::Hash;
 use cretonne::entity_map::{EntityMap, PrimaryEntityData};
-use cretonne::entity_ref::EntityRef;
+use cretonne::entity::EntityRef;
 use cretonne::packed_option::PackedOption;
 use cretonne::packed_option::ReservedValue;
 use std::u32;
@@ -607,7 +607,7 @@ impl<Variable> SSABuilder<Variable>
 
 #[cfg(test)]
 mod tests {
-    use cretonne::entity_ref::EntityRef;
+    use cretonne::entity::EntityRef;
     use cretonne::ir::{Function, InstBuilder, Cursor, CursorBase, Inst, JumpTableData};
     use cretonne::ir::types::*;
     use cretonne::verify_function;