DolphinWX: Add items to visible columns only

Before the columns of the gamelist were filled with content regardless
of their visibility. This led to display bugs when certain columns, for
example the region column, were hidden.

The first problem was the InsertItemInReportView() function because it
refilled all columns with content on every call to update() without
checking for their visibility. While this issue would have easily been solved
by adding conditionals before each column update, the maker column would
have still caused problems for it autohides on resize and those do not
call update(). Therefore it was necessary to move the column update logic
from InsertItemInReportView() to a new one that allows for seperate
modification of an item's columns.

Source/Core/DolphinWX/GameListCtrl.h

@@ -74,6 +74,7 @@ private:
 	wxSize lastpos;
 	wxEmuStateTip *toolTip;
 	void InitBitmaps();
+	void UpdateItemAtColumn(long _Index, int column);
 	void InsertItemInReportView(long _Index);
 	void SetBackgroundColor();
 	void ScanForISOs();
@@ -100,6 +101,8 @@ private:
 
 	void CompressSelection(bool _compress);
 	void AutomaticColumnWidth();
+	void ShowColumn(int column, int width);
+	void HideColumn(int column);
 	void UnselectAll();
 
 	static size_t m_currentItem;