build: finalize support for gcc 4.7, 4.8

this was the missing issue I also mentioned on ML, now I found a solution.
Now gcc 4.6, 4.7 and 4.8 seem to be able to build the codebase.
http://gcc.gnu.org/gcc-4.7/porting_to.html

In instantiation of ‘int t(T) [with T = int]’
  required from here
  error: ‘f’ was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation [-fpermissive]
  note: ‘int f(int)’ declared here, later in the translation unit

To fix, make sure the function f in the code above is declared before first use in function t.

Author: breznak

README.md

@@ -21,7 +21,7 @@ __Clients__ take input data and feed it through encoders, models, and metrics an
 Installation
 ------------
 
-NuPIC requires Python 2.6 (with development headers), GCC, and Make.
+NuPIC requires Python 2.6 (with development headers), GCC (4.6-4.8), and Make.
 
 Add the following to your .bashrc file. Change the paths as needed.
 

nta/math/array_algo.hpp

@@ -3054,6 +3054,35 @@ namespace nta {
     else
       return lp_norm(p, begin, end, take_root);
   }
+  
+  //--------------------------------------------------------------------------------
+  /**
+   */
+  template <typename It>
+  inline void
+  multiply_val(It begin, It end,
+               const typename std::iterator_traits<It>::value_type& val)
+  {
+    {
+      NTA_ASSERT(begin <= end)
+        << "multiply_val: Invalid range";
+    }
+
+    if (val == 1.0f)
+      return;
+
+    for (; begin != end; ++begin)
+      *begin *= val;
+  }
+
+  //--------------------------------------------------------------------------------
+  /**
+   */
+  template <typename T>
+  inline void multiply_val(T& x, const typename T::value_type& val)
+  {
+    multiply_val(x.begin(), x.end(), val);
+  }
 
   //--------------------------------------------------------------------------------
   /**
@@ -4025,35 +4054,6 @@ namespace nta {
     negate(x.begin(), x.end());
   }
 
-  //--------------------------------------------------------------------------------
-  /**
-   */
-  template <typename It>
-  inline void
-  multiply_val(It begin, It end,
-               const typename std::iterator_traits<It>::value_type& val)
-  {
-    {
-      NTA_ASSERT(begin <= end)
-        << "multiply_val: Invalid range";
-    }
-
-    if (val == 1.0f)
-      return;
-
-    for (; begin != end; ++begin)
-      *begin *= val;
-  }
-
-  //--------------------------------------------------------------------------------
-  /**
-   */
-  template <typename T>
-  inline void multiply_val(T& x, const typename T::value_type& val)
-  {
-    multiply_val(x.begin(), x.end(), val);
-  }
-
   //--------------------------------------------------------------------------------
   /**
    */