Added new 64 pin version of base trainer

* Added a new 64 pin version of base trainer. These are the changes:
-> Reduced main connector from 3x30 to 2x30. Now it can accept
microcontroles up to 64 pin, wich is enough for most hobbyst.
-> Redistributed most components to gain some space. Thanks to this
increment, now it is possible to place a full breadboard.
-> Reduced from 8 to only 4 pushbuttons.
-> Added a 7-segment display, model Kingbright SC39-11SRWA. It is
multiplexed with leds. Both can individually be activated or not via two
jumpers.
-> Added 2 power outputs driven by a Microchip MCP14E4 or similar.
-> Added a mini-USB connector type B format.

* Added renders of this new version. They are rendered using Eagle3D and
Povray. Povray file is also included.

* Deleted some gerber files generated, as I think they were not really
necessary.

* Added the same file I sent to IteadStudio to make this new pcb.