Changed the fuse setting for 1284p

Changed the fuse setting for sangunilolu 1284p 8, 16 and 20 Mhz devices.

- Change the boot size from 1024 to 2048.
it was causing the controller to reset into the wrong memory location.
For example, when the brown-out reset due to slow power up supply or the
user pressed the reset button.

- Enable the brown-out reset.
- Enable startup timer for he clock.
- Disable the jtag

Possible Symptons:
- board crashes when the reset button is pressesd. (reset vector wrong
location)
- board fails to boot up correctly whith slow raise power supply. (reset
vector wrong location)
- X axis stepper motor only travel in one direction (Jtag enable)
- Limit switch want trigger. (Jtag enable)
- Unable reprogram the device via bootloader. (caused when the device is
reset and device goes into the wrong reset reset vector)