Enable docker support for centos builds

- Added an option '--buildindocker <osname>' to build.sh
- Fixed bug which caused packaging to be skipped by default.
- Fixed bug which caused tarballs to be generated twice.
- Fixed bug to propagate build params(like debug, nopackage) to docker build.

scripts/common/_common.sh

@@ -11,7 +11,6 @@ while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symli
 done
 COMMONDIR="$( cd -P "$( dirname "$COMMONSOURCE" )" && pwd )"
 
-source "$COMMONDIR/_clang.sh"
 source "$COMMONDIR/_prettyprint.sh"
 source "$COMMONDIR/_rid.sh"