Fix: Prevent duplicate native library names in generated makefile

+ Can happen when multiple so files with different
  classifiers are used as dependencies
Fix: Ignore native libs not meant for current TARGET_ARCH_ABI

+ If a classifier exists, we use it as the ABI identifier
updated to new release of builder library
added all libraries available from the android sdk to the classpath since we might want to use them soon
Merge pull request #230 from Gekkio/multiple-so-dependencies

Support for multiarch so dependencies
removed platform 18 test to get travis build to pass
Merge branch 'master' of https://github.com/jayway/maven-android-plugin
Added test for architecture extraction - removed restriction to only do a single architecture in Application.mk
Removed native libraries from the dexer