Kill off some usages of c_str.

Also changes some function params, but this is ok.
Some simplifications were also able to be made (ie. killing off strcmps with ==, etc).

Source/Core/VideoBackends/OGL/GLExtensions/GLExtensions.cpp

@@ -1755,7 +1755,7 @@ namespace GLExtensions
 
 	// Public members
 	u32 Version() { return _GLVersion; }
-	bool Supports(std::string name)
+	bool Supports(const std::string& name)
 	{
 		return m_extension_list[name];
 	}

Source/Core/VideoBackends/OGL/GLExtensions/GLExtensions.h

@@ -40,7 +40,7 @@ namespace GLExtensions
 
 	// Function for checking if the hardware supports an extension
 	// example: if (GLExtensions::Supports("GL_ARB_multi_map"))
-	bool Supports(std::string name);
+	bool Supports(const std::string& name);
 	
 	// Returns OpenGL version in format 430
 	u32 Version();