do not explode if config[:addons] is an array
Merge branch 'master' of github.com:travis-ci/travis-build
make sure Data::Var#secure? returns true/false
Disable spec failing because of case insensitivity on Mac OSX

I am not sure how this spec ever passed.

Apparently `[ -f Requirements.txt]` always matches on Mac OSX (case
insensitive file system), even if only `requirements.txt` is present.
Therefor this spec will always fail because the bash script runs the
first branch of the `if` statement, not the second one.
Refactor towards sexp changes

Some refactorings and cleanup in order to work towards re-applying
the sexp changes.

This mostly makes all `Build::Script` implementations use
`sh.[dsl_method]` and stops including `Dsl` to `Build::Script`. Instead
`sh` will always be the current `Shell::Node`.
move secure var obfuscation to the dsl
coverity_scan addon (does not have any tests)
firefox addon
sauce_connect addon
android script
C script
clojure script
cpp script
erlang script
go script
haskell script
node_js script
objective_c script
perl script
php script