Removed garbage characters
Removed the infinite recursion bug in STEPattribute

The bug would surface if a STEPattribute instance which has been redefined, has its ShallowCopy function invoked.
Made STEPattributeList thread safe

Couple of functions were identified as vulnerable. The mutex defined in the superclass SingleLinkList was used.
Redefined GetMiEntity API

GetMiEntity function is a part of SDAI_Application_instance class. The function now accepts const char * (instead of char *) as parameter.
Added test for checking thread safety

This test would check thread safety for AppendMultInstance & GetMiEntity functions in class SDAI_Application_instance. The tests failed for both.
Rest of the functions were not checked since the locking in them was trivial.
Internal changes in sdaiApplication_instance.cc

These changes have been done to facitilate the use of mutexes to make the SDAI_Application_instance class thread safe. (No mutex has been used introduced yet)
Made SDAI_Application_instance thread safe.

This was done by introducing a mutex for each SDAI_Application_instance.
AppendMultInstance was made thread safe by doing hand to hand locking.
GetMiEntity was made thread safe acquiring locks in increasing order and releasing locks in decreasing order.
The checks in sdaiApplication_instance_thread_safety_test now pass.