redo: remove -ffreestanding
redo: use -fno-jump-tables
redo: use -funsigned-bitfields
redo: use -fshort-enums
redo: major overhaul

add description to file header
document avr-gcc 4.8 brokenness
compute avrdude flags dynamically
source configuration files for microcontroller and programmer
move -std=gnu11 to CFLAGS_STD
add -Wl,--gc-sections
remove -Waddr-space-convert (avr-gcc 4.8 specific)
remove -fno-diagnostics-show-caret (avr-gcc 4.8 specific)
combine CFLAGS parts array-wise to avoid extra spaces
remove OUT_HEX target
program OUT_BIN directly
make quotes more consistent
add fuse avrdude target
add term avrdude target
cfg: add configuration files for atmega324a, dragon_jtag, usbasp