Enable building Scala 2.9.2 applications for Android using OpenJDK 1.7

Fedora 17+ has OpenJDK 1.7. Building a Scala App using sbt, produces error messages like the one below:

[error] (My_Android_Project/android:proguard) java.io.IOException: Can't read [/home/shailesh/projects/android/my_android_project/target/scala-2.9.2/classes] (Can't process class [my/android/project/R.class] (Unsupported version number [51.0] for class format))

See https://github.com/jberkel/android-plugin/issues/102 for a similar error.

So, we just target JDK 1.6, and things work merrily.
Merge pull request #8 from shaileshkhandekar/master

Enable using JDK 1.7
Adds SBTEclipse+AndroidProguardScala support
Fixed some properties
Removed NDK by default
Changed eclipse command to generate TypedResources
Updated readme
Fixed forgotten bad import
Generate typed resources before any project
Added exclusion pattern for R.java
Updated README with some more information
Changed default Execution Environment to Java 1.6
Move uses-sdk block to beginning of manifest as recommended by ADT
Add ability to specify separate minSdkVersion and targetSdkVersion
Add android code version settings to manifest.