src: improve SCardConnect interface

- We can optionally pass the share_mode and preferred_protocol options. They are
  optional to keep backwards compatibility.
- Update README
- Define constants in C++ land.

lib/pcsclite.js

@@ -67,10 +67,18 @@ module.exports = function() {
     return p;
 };
 
-CardReader.prototype.connect = function(cb) {
+CardReader.prototype.connect = function(options, cb) {
+    if (typeof options === 'function') {
+        cb = options;
+        options = undefined;
+    }
+
+    options = options || {};
+    options.share_mode = options.share_mode || this.SCARD_SHARE_EXCLUSIVE;
+    options.protocol = options.protocol || this.SCARD_PROTOCOL_T0 | this.SCARD_PROTOCOL_T1;
 
     if (!this.connected) {
-        this._connect(cb);
+        this._connect(options.share_mode, options.protocol, cb);
     } else {
         cb();
     }
@@ -109,18 +117,6 @@ CardReader.prototype.control = function(data, control_code, res_len, cb) {
     });
 };
 
-CardReader.prototype.SCARD_STATE_UNAWARE = 0x0000;
-CardReader.prototype.SCARD_STATE_IGNORE = 0x0001;
-CardReader.prototype.SCARD_STATE_CHANGED = 0x0002;
-CardReader.prototype.SCARD_STATE_UNKNOWN = 0x0004;
-CardReader.prototype.SCARD_STATE_UNAVAILABLE = 0x0008;
-CardReader.prototype.SCARD_STATE_EMPTY = 0x0010;
-CardReader.prototype.SCARD_STATE_PRESENT = 0x0020;
-CardReader.prototype.SCARD_STATE_ATRMATCH = 0x0040;
-CardReader.prototype.SCARD_STATE_EXCLUSIVE = 0x0080;
-CardReader.prototype.SCARD_STATE_INUSE = 0x0100;
-CardReader.prototype.SCARD_STATE_MUTE = 0x0200;
-
 // extend prototype
 function inherits(target, source) {
     for (var k in source.prototype) {