[birt-dev]CheckIn: Fix bugs in script class loader

["Wei Yan" <wyan@xxxxxxxxxxx>]

Title: [birt-dev]CheckIn: Fix bugs in script class loader

- Summary:

- Bugzilla Bug (s) Resolved:

- Description:
        The user can define the JARs used in the report desgin. Report engine calls the MODEL API to get the JARs list then loads those JARs in script execution. The return value of the MODEL Api is ScriptLibHandler instead of the ScriptLib. It causes the engin throws out an ClassCastException.

- Tests Description  :
        Manul Test

- Notes to Build Team:

- Notes to Developers:

- Notes to QA:  
 
- Notes to Documentation:  

- Files Edited:
cvs ci -m "fix bugs in app class loader" -l "/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java"

- Files Added:

- Files Deleted

-Wei Yan