Applying NR 1 to CalculatorVector.h (#491)

Applied [NR 1](https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rnr-top) from the ISO C++ Guidelines to CalculatorVector.h

### Description of the changes:
- Move towards understandable and maintainable code

src/CalcManager/CalculatorVector.h

@@ -16,16 +16,15 @@ class CalculatorVector
 public:
     ResultCode GetAt(_In_opt_ unsigned int index, _Out_ TType* item)
     {
-        ResultCode hr = S_OK;
         try
         {
             *item = m_vector.at(index);
         }
         catch (const std::out_of_range& /*ex*/)
         {
-            hr = E_BOUNDS;
+            return E_BOUNDS;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode GetSize(_Out_ unsigned int* size)
@@ -36,35 +35,32 @@ public:
 
     ResultCode SetAt(_In_ unsigned int index, _In_opt_ TType item)
     {
-        ResultCode hr = S_OK;
         try
         {
             m_vector[index] = item;
         }
         catch (const std::out_of_range& /*ex*/)
         {
-            hr = E_BOUNDS;
+            return E_BOUNDS;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode RemoveAt(_In_ unsigned int index)
     {
-        ResultCode hr = S_OK;
         if (index < m_vector.size())
         {
             m_vector.erase(m_vector.begin() + index);
         }
         else
         {
-            hr = E_BOUNDS;
+            return E_BOUNDS;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode InsertAt(_In_ unsigned int index, _In_ TType item)
     {
-        ResultCode hr = S_OK;
         try
         {
             auto iter = m_vector.begin() + index;
@@ -72,14 +68,13 @@ public:
         }
         catch (const std::bad_alloc& /*ex*/)
         {
-            hr = E_OUTOFMEMORY;
+            return E_OUTOFMEMORY;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode Truncate(_In_ unsigned int index)
     {
-        ResultCode hr = S_OK;
         if (index < m_vector.size())
         {
             auto startIter = m_vector.begin() + index;
@@ -87,23 +82,22 @@ public:
         }
         else
         {
-            hr = E_BOUNDS;
+            return E_BOUNDS;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode Append(_In_opt_ TType item)
     {
-        ResultCode hr = S_OK;
         try
         {
             m_vector.push_back(item);
         }
         catch (const std::bad_alloc& /*ex*/)
         {
-            hr = E_OUTOFMEMORY;
+            return E_OUTOFMEMORY;
         }
-        return hr;
+        return S_OK;
     }
 
     ResultCode RemoveAtEnd()
@@ -120,12 +114,12 @@ public:
 
     ResultCode GetString(_Out_ std::wstring* expression)
     {
-        ResultCode hr = S_OK;
         unsigned int nTokens = 0;
-        std::pair<std::wstring, int> currentPair;
+        ResultCode hr = this->GetSize(&nTokens);
-        hr = this->GetSize(&nTokens);
         if (SUCCEEDED(hr))
         {
+
+            std::pair<std::wstring, int> currentPair;
             for (unsigned int i = 0; i < nTokens; i++)
             {
                 hr = this->GetAt(i, &currentPair);