Move build.log into the build folder

Another effort to de-clutter the root folder
Upgrade to use core library version 0.80.3
Merge pull request #634 from realm/ez-build-log

Move build.log into the build folder
Merge pull request #640 from realm/ks-use-core-ver-0.80.3

Upgrade to use core library version 0.80.3
Merge branch 'master' into ez-buildbin

* master:
  Upgrade to use core library version 0.80.3
  Move build.log into the build folder
delete build/bin, otherwise the symlink will fail