move var metadata from LambdaInfo.ast to fields of LambdaInfo

LambdaInfo.ast is now LambdaInfo.code, and is just an array of
statements

store LambdaInfo objects in the tfunc cache, instead of just ASTs

now type inference operates on InferenceState.linfo in place, and
eventually copies the results to InferenceState.destination if
necessary.

base/expr.jl

@@ -133,7 +133,7 @@ end
 
 function popmeta!(body::Expr, sym::Symbol)
     body.head == :block || return false, []
-    found, metaex = findmeta_block(body)
+    found, metaex = findmeta_block(body.args)
     if !found
         return false, []
     end
@@ -151,23 +151,29 @@ function popmeta!(body::Expr, sym::Symbol)
     false, []
 end
 popmeta!(arg, sym) = (false, [])
+function popmeta!(body::Array{Any,1}, sym::Symbol)
+    ex = Expr(:block); ex.args = body
+    popmeta!(ex, sym)
+end
 
 function findmeta(ex::Expr)
     if ex.head == :function || (ex.head == :(=) && typeof(ex.args[1]) == Expr && ex.args[1].head == :call)
         body::Expr = ex.args[2]
         body.head == :block || error(body, " is not a block expression")
-        return findmeta_block(ex)
+        return findmeta_block(ex.args)
     end
     error(ex, " is not a function expression")
 end
 
-function findmeta_block(ex::Expr)
-    for a in ex.args
+findmeta(ex::Array{Any,1}) = findmeta_block(ex)
+
+function findmeta_block(exargs)
+    for a in exargs
         if isa(a, Expr)
             if (a::Expr).head == :meta
                 return true, a::Expr
             elseif (a::Expr).head == :block
-                found, exb = findmeta_block(a)
+                found, exb = findmeta_block(a.args)
                 if found
                     return found, exb
                 end