Merge pull request #19 from arneolavhal/fix_weapon_oob

! Fixed out of bounds access on gamepadweapons.
Further correction to number of weapons

(sizeof(gamepadweapons)/sizeof(gamepadweapons[0])) - 1 = 7 - 1 = 6, so
remove the " - 1"
Allow two weapons on one gamepad control

If two gamepad_weapon[x] variables in default.cfg are assigned to the
same gamepad control, pressing that control will toggle between the two
weapons.
Fix some warnings

Raised warning level from 3 to 4 and fixed a few warnings.
Exit with error if blood splat lumps not found

Older versions of doomretro.wad don't have the blood splat lumps. The
game will still load, but crash at the first sign of blood.
Upgrade to Visual Studio Express 2013

Microsoft Visual Studio Express 2013 for Windows Desktop is available
for free from http://www.visualstudio.com/.
Update XInput dependencies

Newer compiler has different name for XInput 9.1.0 library. Update this
otherwise you get an error saying "XINPUT1_4.dll is missing" on Windows
7 or earlier.
Merge branch 'master' of github.com:bradharding/doomretro