add blind transfer support to the code.

Thank you for this great project, its amazing.

i installed it , and when im using the blind tranfer action, there is an error returned.

after downloading and compiling the project, i found out that this function exists :

//code

LONG
TSPIAPI
TSPI_lineBlindTransfer(
DRV_REQUESTID dwRequestID,
HDRVCALL hdCall,
LPCWSTR lpszDestAddress,
DWORD dwCountryCode)
{
return (LINEERR_OPERATIONFAILED);
}

//code
which mean that the component does not support blind transfer action sent to the tapi.

i even verified with a custm trace message that showed up that it does end up in this function.

why dont you just call the redirect function that send the command in the asterisk,

AC_RESULT ASTProvider::Redirect( std::string channel,
std::string extraChannel,
std::string extension,
std::string context)

//some code

command = "Action: Redirect\r\n";
command += "Channel: " + channel ;
command += "\r\n";
if (extraChannel.size()>0) {
    command += "ExtraChannel: " + extraChannel ;
    command += "\r\n";
}
command += "Exten: " + extension ;
command += "\r\n";
command += "Context: " + context ;
command += "\r\n";
command += "Priority: 1" ;
command += "\r\n";
/* Redirect action does not support Async mode  */
command += "ActionID: " + invokeId;
command += "\r\n\r\n";
SendCommand(command);

//some more code