Remove tea-ci drone.yml and switch status badge to Appveyor

.drone.yml

@@ -1,17 +0,0 @@
-# Build configure for https://www.tea-ci.org (fork of Drone CI with Msys2 support)
-build:
-  image: teaci/msys$$arch
-  pull: true
-  shell: msys$$arch
-  commands:
-    - pacman -S --needed --noconfirm --noprogressbar mingw-w64-cross-gcc mingw-w64-cross-crt-git
-    - ./configure
-    - make
-    - make tests
-    - build/trivial_test.exe
-    - mintty --log - --exec build/winpty.exe cmd /c ver | grep Windows
-
-matrix:
-  arch:
-    - 64
-    - 32

README.md

@@ -1,6 +1,6 @@
 # winpty
 
-[![Build Status](https://tea-ci.org/api/badges/rprichard/winpty/status.svg)](https://tea-ci.org/rprichard/winpty)
+[![Build Status](https://ci.appveyor.com/api/projects/status/69tb9gylsph1ee1x/branch/master?svg=true)](https://ci.appveyor.com/project/rprichard/winpty/branch/master)
 
 winpty is a Windows software package providing an interface similar to a Unix
 pty-master for communicating with Windows console programs.  The package