fix an error about android-maven-plugin not finding aapt

This updates android-maven-plugin to the latest stable version. Without this commit, I get the following error while building:

gregg@mbp pt %mvn3 clean install                                            [1]
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building PageTurner 2.2-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.4.1:clean (default-clean) @ PageTurner ---
[INFO] Deleting /home/gregg/workspace/pt/target
[INFO] 
[INFO] --- android-maven-plugin:3.0.0:generate-sources (default-generate-sources) @ PageTurner ---
[DEBUG] Expanding: /home/gregg/.m2/repository/com/actionbarsherlock/actionbarsherlock/4.2.0/actionbarsherlock-4.2.0.apklib into /home/gregg/workspace/pt/target/unpack/apklibs/com.actionbarsherlock_actionbarsherlock_apklib_4.2.0
[DEBUG] expand complete
[INFO] ANDROID-904-002: Found aidl files: Count = 0
[INFO] ANDROID-904-002: Found aidl files: Count = 0
[INFO] ANDROID-904-002: Found aidl files: Count = 0
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.844s
[INFO] Finished at: Thu Aug 22 07:31:47 MDT 2013
[INFO] Final Memory: 9M/150M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.0.0:generate-sources (default-generate-sources) on project PageTurner: Execution default-generate-sources of goal com.jayway.maven.plugins.android.generation2:android-maven-plugin:3.0.0:generate-sources failed: Could not find tool 'aapt'. Please provide a proper Android SDK directory path as configuration parameter <sdk><path>...</path></sdk> in the plugin <configuration/>. As an alternative, you may add the parameter to commandline: -Dandroid.sdk.path=... or set environment variable ANDROID_HOME. -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException