move functions within main.c to dfu_util.c/.h
add CFLAG -Wextra and lot of type casts
new parameter I to ignore suffix mismatch, revise help messages
msvc folder, add _chsize_s(ftruncate on w32), fix lmdfu.c(memleak)

Signed-off-by: Pascal Schweizer <pascal.schweizer@siemens.com>