Replicates all needed state between expanded functions

commit 5e6f06cf59
Author: Aaron Gutierrez <gutierrez.aaron.m@gmail.com>
Date:   Thu May 11 15:42:11 2017 -0400

    Fixed issue with aliasing local variables

    ISPC++ now produces valid code, or an appropriate error message, for all
    of my test cases.

commit bfe723e1b7
Author: Aaron Gutierrez <gutierrez.aaron.m@gmail.com>
Date:   Thu May 11 03:09:38 2017 -0400

    Actually copy the AST.

    Type replacement works except for function parameters.

commit f65b3e6300
Author: Aaron Gutierrez <gutierrez.aaron.m@gmail.com>
Date:   Thu May 11 01:19:50 2017 -0400

    [WIP] Remove cases for ForeachStmt and SymbolExpr

commit 2e28640860
Merge: 6a91c5d d020107
Author: Aaron Gutierrez <gutierrez.aaron.m@gmail.com>
Date:   Wed May 10 23:13:40 2017 -0400

    Merge branch 'master' into copy_ast

commit 6a91c5d5ac
Author: Aaron Gutierrez <gutierrez.aaron.m@gmail.com>
Date:   Wed May 10 11:11:39 2017 -0400

    Attempt to replicate AST when expanding polytypes

sym.h

@@ -141,7 +141,7 @@ public:
         with a symbol defined at the same scope.  (Symbols may shaodow
         symbols in outer scopes; a warning is issued in this case, but this
         method still returns true.) */
-    bool AddVariable(Symbol *symbol);
+    bool AddVariable(Symbol *symbol, bool issueScopeWarning=true);
 
     /** Looks for a variable with the given name in the symbol table.  This
         method searches outward from the innermost scope to the outermost,