LogManager class refactored

In LogManager class
* New method GetClassFullName() created from the common code extracted from GetCurrentClassLogger() and GetCurrentClassLogger(Type) methods. 
* Try Catch block moved from LogManager static constructor into SetupTerminationEvents() method. 
* Comments and code reformatted.

**Note:** The string GetClassFullName() method in LogManager class should be tested in SilverLight.