Multiple db's: $DB and $EXTENSIONS are escaped

In order to make "for" loop works with multiple values in $DB and $EXTENSIONS
we have to escape these variables.

Example: DB="db1 db2" EXTENSIONS="ex1 ext2"

Without escapint it will cause shell error.
Merge pull request #26 from ykhalyavin/escape_variables

Multiple db's: $DB and $EXTENSIONS are escaped