added getLast function  and some comments

Change-Id: I84680cfd43d5933e83f1ad46be2f616ea525694a
added some comments

Change-Id: I5b01757e8ad52d28b241f4555c1a030c0912b91e
added new benchtest project to xcode workspace

Change-Id: I07fe7bf802fc0613b7c40deee3014424464812c3
modified the xcode workspace and new project addition.

The workspace update is for isolate all project, now the developer need to compile by hand
all the referenced library for the project (ex CUTest ned chaos common and cu_toolkit that need to be
compiled by hand). This permit to imporve speed during xcode development debug sessione for compilation.
New project is the Benchtest simulation cod to test chaos installation

Change-Id: I2ad191b4e5c6b68b62ce07c163841ddfa2228b08