1. make my groovy code more java like
add @groovy.transform.TypeChecked and @groovy.transform.CompileStatic to
eliminate runtime surprise
2. add strict checking before 'pack' task
3. all boot.img.clear* will be hashed and the hash code will be compared to
assert equation
4. upgrade gradle and groovy version
remove original abootimg by Gilles Grandou <gilles@grandou.net>
create groovy abootimg and mkbootimg
previous bootimg.cfg moved to bootimg.json
update doc: README.expert.md
cfig