Import SSL in Windows (get.exe)

Closes: https://github.com/espressif/arduino-esp32/pull/820

tools/get.py

@@ -80,6 +80,7 @@ def get_tool(tool):
         print('Downloading ' + archive_name);
         sys.stdout.flush()
         if 'CYGWIN_NT' in sys_name:
+            import ssl
             ctx = ssl.create_default_context()
             ctx.check_hostname = False
             ctx.verify_mode = ssl.CERT_NONE