feature: Add GetGlyph

[Tralenor]

adds player:GetGlyph(slotIndex) (requested by @55Honey in #152 (comment)_)

how to test

add a scripting file with:

local function OnPlayerCommand(event, player, command)
  if (command == "add_glyph") then
        print("reached_command: add glyph")
        player:SetGlyph(190,0)
        player:SetGlyph(702,3)

        player:Say("glyph in slot 0: "..player:GetGlyph(0),0)

        player:Say("glyph in slot 1: "..player:GetGlyph(1),0)

        player:Say("glyph in slot 3: "..player:GetGlyph(3),0)
        return false
    end
end

RegisterPlayerEvent(42, OnPlayerCommand)

On a paladin execute command ".add_glyph" in chat
Check that output matches input as written in script (190,0,702)

also credit to @kissingers who created a PR on this topics on the same day. #177

[kissingers]

Good, so I can call back my pull...

[Tralenor]

Good, so I can call back my pull...

@kissingers Oh sorry, I did not see that you created one yesterday as well. If you prefer I can close this one and you could re-open yours.

[kissingers]

It seems your code and doc more good than me, so need not re-open.

[55Honey]

Thanks for the PR!