Here is a 'boxed' version made with a professionally printed PCB (cheap online service from EasyEDA). The PCB is sized in order to perfectly fit inside a, widely available, 100x60x25mm plastic box (on ebay here).
UPDATE FEBRUARY 2018
Added Voltage Divider (R7-R8 in the schematic) for HC-06 RX pin.
Added Gerber files for download and updated Arduino code.
UPDATE MAY2018
Added Voltage Regulator 7808 for ProMini Raw power.
UPDATE OCT2018
Bug fix in Arduino and Tcl code (Case 00).