Don't read from disk when checking volume type

Should be faster than relying on the OS to cache the magic words.
Also gets rid of the odd recursive call in VolumeDirectory.

Source/Core/Core/Boot/Boot.cpp

@@ -214,8 +214,7 @@ bool CBoot::BootUp()
 		if (pVolume == nullptr)
 			break;
 
-		bool isoWii = DiscIO::IsVolumeWiiDisc(pVolume);
-		if (isoWii != _StartupPara.bWii)
+		if (pVolume->IsWiiDisc() != _StartupPara.bWii)
 		{
 			PanicAlertT("Warning - starting ISO in wrong console mode!");
 		}
@@ -237,7 +236,7 @@ bool CBoot::BootUp()
 		}
 
 
-		_StartupPara.bWii = VolumeHandler::IsWii();
+		_StartupPara.bWii = VolumeHandler::IsWiiDisc();
 
 		// HLE BS2 or not
 		if (_StartupPara.bHLE_BS2)
@@ -295,7 +294,7 @@ bool CBoot::BootUp()
 		{
 			BS2Success = EmulatedBS2(dolWii);
 		}
-		else if (!VolumeHandler::IsWii() && !_StartupPara.m_strDefaultISO.empty())
+		else if (!VolumeHandler::IsWiiDisc() && !_StartupPara.m_strDefaultISO.empty())
 		{
 			VolumeHandler::SetVolumeName(_StartupPara.m_strDefaultISO);
 			BS2Success = EmulatedBS2(dolWii);
@@ -345,7 +344,7 @@ bool CBoot::BootUp()
 		{
 			BS2Success = EmulatedBS2(elfWii);
 		}
-		else if (!VolumeHandler::IsWii() && !_StartupPara.m_strDefaultISO.empty())
+		else if (!VolumeHandler::IsWiiDisc() && !_StartupPara.m_strDefaultISO.empty())
 		{
 			VolumeHandler::SetVolumeName(_StartupPara.m_strDefaultISO);
 			BS2Success = EmulatedBS2(elfWii);

Source/Core/Core/Boot/Boot_BS2Emu.cpp

@@ -21,8 +21,6 @@
 #include "Core/HW/Memmap.h"
 #include "Core/PowerPC/PowerPC.h"
 
-#include "DiscIO/VolumeCreator.h"
-
 void CBoot::RunFunction(u32 _iAddr)
 {
 	PC = _iAddr;
@@ -320,7 +318,7 @@ bool CBoot::EmulatedBS2_Wii()
 
 	// Execute the apploader
 	bool apploaderRan = false;
-	if (VolumeHandler::IsValid() && VolumeHandler::IsWii())
+	if (VolumeHandler::IsValid() && VolumeHandler::IsWiiDisc())
 	{
 		// Set up MSR and the BAT SPR registers.
 		UReg_MSR& m_MSR = ((UReg_MSR&)PowerPC::ppcState.msr);