Added sdks folder to .gitignore and android external build script to tools
handle not having a .ios file if it's not necessary
skip the deps section if it's not needed
Merge branch 'feature/android_externals' of https://github.com/montegoulding/livecode into feature-externals_api_v5
[[ ExternalsApiV5 ]] Tweaks to .gitignore.
Merge commit '4a19c3635f073430a0481d1dbfc4af4ac21aeae6' into feature/externals_v5