updates Tokens object initialization

[ffunenga]

I forgot to check the C++ compilation, Tried it now with the following commands and it runned without trouble.

$ python docopt_c.py -o docopt.c -t template.c example.docopt 
$ g++ -Wall example.c -o example
$ ./example 
--help == false
--version == false
--tcp == false
--serial == false
--host == localhost
--port == 1234
--timeout == 10
--baud == 9600

[kblomqvist]

Looks good to me and I like the style. Thanks.