add readme
update branches for platform and config
replace core with "reach"-image-minimal
Set daisy-next as the branch for meta-reach

Signed-off-by: Mario Domenech Goulart <mario@ossystems.com.br>
Use daisy-next for reach-platform

Signed-off-by: Mario Domenech Goulart <mario@ossystems.com.br>
default.xml: Fix Poky and O.S. Systems' scripts to use daisy

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>