Fixing timing issue with resetting Esplora

It appears that at least on my Mac some assumptions about Esplora are slightly different:
  * As soon as we set COM1 to 1200 baud, Esplora resets nearly instantaneously, and while I do see these ports disappear momentarily, I was unable to catch that in code even after checking every 1ms after closing serial port.  It does get reset, it's just that by the time we expect serial ports to disappear, it's already too late and they are all back. Literally I called ```Serial.list()``` right after reset, and it was too late. Could be some OS-level blocking happening on the serial interface that's causing this.

I worked around this case by switching the non-detection case of the ```wait_for_com_Port_to_appear()``` function into a warning instead, and allowing us to continue after 2 seconds of unsuccessfully trying to detect port disappearance.  2 seconds should be plenty on even the slowest computers, but it leaves plenty of time for Esplora to start receiving the program (Esplora keeps bootloader open for input for 8 seconds after reset).  So in my case, Eclipse just pauses for 2 seconds and then continues to the next step, and this simply works. I wish there was a way to detect the disappearance, but I think that as soon as we call ```Serial.list()``` after resetting the port, we are already missing the opportunity and the serial ports are back.  

An alternative could be to introduce environment variable that simply disables call to ```wait_for_com_Port_to_appear()``` function even if the board is Esplora/Leonardo/etc.  That, at least, gives users flexibility to configure this behavior.

Additionally, please note that on my iMac Esplora (and every other Arduino board) provides not one, but two USB/serial ports ```cu.xxx``` and ```tty.xxx```. Some of the assumptions in the ```wait_for_com_Port_to_appear``` function seems to assume that only one serial port is added/removed by the board. I am referring to this check:

```java
while (OriginalPortsCopy.size() != 1);
```