Changed lingering header include guards to pragma once.

Some headers where using #ifndef to guard being including multiple times. But most were using pragma once. So for consistency I changed them all to use pragma once.
VideoCommon: Cache native vertex formats

We are used to have a 1:1 mapping of GX vertex formats and the native (OGL + D3D) ones, but there are by far more GX ones.
This new cache maps them directly so that we don't flush on GX vertex format changes as long as the native one doesn't change.

The idea is stolen from galop1n.
Keep device type EXIDEVICE_MEMORYCARDFOLDER for gci folder.

This fixes loading save states when type mismatches.
Common: Make DoContainer within PointerWrap private.

This shouldn't really be exposed as a public function and should only be called through other Do class functions that take a container type as a parameter.
VideoCommon: Remove some unused constants from VertexShaderGen.h.
Merge pull request #564 from lioncash/constants

Merge pull request #564 from lioncash/constants

VideoCommon: Remove some unused constants from VertexShaderGen.h.
Merge pull request #559 from RachelBryk/gci-folder-state

Merge pull request #559 from RachelBryk/gci-folder-state

Keep device type EXIDEVICE_MEMORYCARDFOLDER for gci folder.
Merge pull request #563 from lioncash/pointerwrap

Common: Make DoContainer within PointerWrap private.
Fix hiding size column in game list.
Merge pull request #565 from RachelBryk/size-column

Fix hiding size column in game list.
Common: Using size_t in PointerWrap's DoContainer apparently causes crashes. Fixes this.
Merge pull request #566 from lioncash/fix-crash

Common: Using size_t in PointerWrap's DoContainer apparently causes crashes
ConfigManager: fix alignment
Merge pull request #567 from degasus/master

ConfigManager: fix alignment
Merge pull request #463 from degasus/vertex_format_cache

VideoCommon: Cache native vertex formats
Merge pull request #546 from workhorsy/header_guard_to_pragma_once

Changed lingering header include guards to pragma once.