FPC: got RX working, got client over usart somehow working..., see detailed commit msg

* using WITH_FPC:
  * activate basic usart
  * no double buffer for now, no interrupt
  * usart_dataavailable/usart_readbuffer/usart_writebuffer, to demo it:
    * pm3 client over USB, minicom over usart
    * analyse a d 414243
* using WITH_FPC_HOST:
  * it implies WITH_FPC as it's based on it
  * control pm3 with client over usart
  * EXPERIMENTAL! still some frame desync issues
  * you can connect both from usart & USB with two pm3 clients
    * actually you *have* to connect USB for the moment because
      it's used to send debug messages about buggy usart... See Dbprintf_usb below
  * "sessions": msgs are directed to the latest client to have sent a cmd
  * Dbprintf_usb macro to send msgs to USB client to help debugging usart...
  * We now have an option to run client at different speed as usart is 115200:
    client/proxmark3 /dev/ttyUSB0 -b 115200
  * Consequently, argc,argv handling is a bit revamped, it was so messy...
  * USB and flashing are still at 460800, don't try flashing over usart yet ^^

client/proxmark3.c

@@ -259,6 +259,9 @@ int main(int argc, char *argv[]) {
     bool addLuaExec = false;
     char *script_cmds_file = NULL;
     char *script_cmd = NULL;
+    char *lastarg = NULL;
+    char *port = NULL;
+    uint32_t speed = 0;
 
     /* initialize history */
     using_history();
@@ -272,7 +275,9 @@ int main(int argc, char *argv[]) {
         return 1;
     }
 
-    for (int i = 1; i < argc; i++) {
+    uint32_t i = 1;
+    port = argv[i++];
+    for (i; i < argc; i++) {
 
         // helptext
         if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "-help") == 0) {
@@ -291,29 +296,58 @@ int main(int argc, char *argv[]) {
         if (strcmp(argv[i], "-f") == 0 || strcmp(argv[i], "-flush") == 0) {
             SetFlushAfterWrite(true);
             PrintAndLogEx(INFO, "Output will be flushed after every print.\n");
+            continue;
+        }
+
+        // set baudrate
+        if (strcmp(argv[i], "-b") == 0 || strcmp(argv[i], "-baud") == 0) {
+            uint32_t tmpspeed = strtoul(argv[i+1], NULL, 10);
+            if ((tmpspeed == ULONG_MAX) || (tmpspeed == 0)) {
+                PrintAndLogEx(WARNING, "ERROR: invalid baudrate: %s %s\n", argv[i], argv[i+1]);
+                return 1;
+            }
+            speed = tmpspeed;
+            i++;
+            continue;
         }
 
         // wait for comport
         if (strcmp(argv[i], "-w") == 0 || strcmp(argv[i], "-wait") == 0) {
             waitCOMPort = true;
+            continue;
         }
 
         // execute pm3 command
         if (strcmp(argv[i], "-c") == 0 || strcmp(argv[i], "-command") == 0) {
             executeCommand = true;
+            continue;
         }
 
         // execute lua script
         if (strcmp(argv[i], "-l") == 0 || strcmp(argv[i], "-lua") == 0) {
             executeCommand = true;
             addLuaExec = true;
+            continue;
+        }
+
+        if (i < argc - 1) {
+            // We got an unknown parameter
+            PrintAndLogEx(WARNING, "WARNING: ignoring invalid parameter: %s\n", argv[i]);
+        }
+
+        if (i == argc - 1) {
+            // We got presumably a command or a filename
+            lastarg = argv[argc - 1];
         }
     }
 
+    if (speed == 0)
+        speed = 460800;
+
     // If the user passed the filename of the 'script' to execute, get it from last parameter
-    if (argc > 2 && argv[argc - 1] && argv[argc - 1][0] != '-') {
+    if (lastarg) {
         if (executeCommand) {
-            script_cmd = argv[argc - 1];
+            script_cmd = lastarg;
 
             while (script_cmd[strlen(script_cmd) - 1] == ' ')
                 script_cmd[strlen(script_cmd) - 1] = 0x00;
@@ -336,7 +370,7 @@ int main(int argc, char *argv[]) {
                 PrintAndLogEx(SUCCESS, "execute command from commandline: %s\n", script_cmd);
             }
         } else {
-            script_cmds_file = argv[argc - 1];
+            script_cmds_file = lastarg;
         }
     }
 
@@ -358,7 +392,7 @@ int main(int argc, char *argv[]) {
     set_my_executable_path();
 
     // try to open USB connection to Proxmark
-    usb_present = OpenProxmark(argv[1], waitCOMPort, 20, false);
+    usb_present = OpenProxmark(port, waitCOMPort, 20, false, speed);
 
 #ifdef HAVE_GUI