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.
Merge pull request #479 from ie-zero/Refactor_LogManager

LogManager class refactored