generate proguard config from aapt -G and use it in proguard

as now aapt tool can generate proguard config with used system components
(Fragments, Views, Activities, Services and Application) we can use it in proguard task to
decrease custom proguard config
remove unnecessary proguard options, as they will be generated by aapt -G
Remove timestamp from snapshot version
Change package name to sbtandroid, following sbt-closure and sbt-dropbox-plugin
Change artifact name to sbt-android to match sbt-closure
[fix] No Apklib extraction for the provided scope
Add resPath task to allow specifying additional resource directories
Fix aaptGenerateTask to use resource dirs from resPath
Fixing aapt, idl and dx paths from new build-tools
Add build tools detection code from fxthomas
Improvements and cleanup for 0.7-SNAPSHOT

  * Version bump and lots of comments
  * New plugin structure using configurations
  * New Proguard rules, automatic generation (aapt -G)
  * Ability to use a custom Proguard configuration file
  * Easier classpath management
  * Easier preloading, with support for arbitrary libraries
  * Many fixes (ApkLibs, test projects,...)
  * Device-specific commands don't exist anymore, use adbTarget
  * Setting for the default IntelliJ configuration
  * Fixed old "market" terminology
[fix] Fixed default keyalias missing
[fix] "apk" and "release" delegates in Global
[fix] Fixed "release" in Global scope
[feature] Preliminary AAR library support
[feature] Typed resource on/off flag
[fix] Include apklibs from unmanagedBase
[fix] NPE when filtering non-existing unmanagedBase
[feature] Settings for standard Ant projects
[fix] No lib/ created if it doesn't exist