Switch to VC++ 2013 on Windows

Remove the faux-variadic make_unique since 2013 has real variadic
templates.

Switch to the non-deprecated windows version check functions.

Switch to the develop branch of boost since master doesn't fully support
VS 2013 atm.

Fix some assorted compilation errors.

Hardcode the paths to a bunch of Visual Studio things since it's now
expanding the relevant macros to nothing for whatever reason.
Fix test compilation on windows
Use initializer lists in some places
Use NSDMIs where applicable
Bump required version of wx to 3.0.0
Remove #ifs for older versions of wx
Use the new much shorter event names
Don't use uniform initialization for structs because VC++ 2013 is buggy
Fix compilation with boost 1.52. Closes #1670.
Add semicolons to things that apparently sometimes need semicolons
Delete pre-3.0 hotkey/option migration information
Switch to using the VC++ 12 redist in the portable installer
Use raw string literals for regular expressions where useful
Switch to unpatched libass since it's compilable with VC++ 2013
Cut down on magic numbers in the drawing code for the x/y rotate grid
Make the X/Y rotation grid much bigger

This is still a totally arbitrary size. Maybe it should be customizable
or adaptive somehow?
Apply the line's shear to the x/y rotation grid
Build stuff with /Gw

It's not very useful, but it doesn't appear to have any downsides.
Merge branch 'master' of github.com:Aegisub/Aegisub into retina
Fix the default angle for styles