Simplifying object handling code in IE driver.

COM objects are now correctly referenced everywhere via smart pointers,
and use of some aliased types is now replaced by the C++ primitives.
Refactoring IE element finder to make clearer when Sizzle is used.

Previously, it was not as easy to determine from IEDriverServer.exe logs
when Sizzle was being used for finding elements by CSS selector. It is now
explicitly called out and logged. Also, it now insures that the automation
atoms are being used when Sizzle is not necessary.
Correcting type warning in x64 compilation
Updating IE prebuilts