Various fixes backported from AppSync Unified

* Use $THEOS variable instead of using symlink to /opt/theos
* Add armv7s slice
* Add sublime-project
* Remove unused duplicated/symlinked source files
* Added YANG_ASU and KAREN_ASU (unused here) to Tweak.x - use -DYANG_ASU in the Makefile (already added in the commit)