Added dalvik in PLATFORM_MAP
Added commits https://github.com/ybart/bundler/commit/f7368a739525481da58905242bb5c7cf4b311ecb
and https://github.com/ybart/bundler/commit/e61f47b7e2cb543479324602e6d46cab304596d2
Call to SpecSet.for in SpecSet.materialize now checks if a platform
was specified in bundler.
Added new Platform constant DALVIK