Remove unnecessary casts w/ automated refactoring

Fixes for CA 1800 Performance rules. These were the ones I could fix
using automated refactorings.
Move nullcheck to the top

This specific code branch is repeated. This is the first step in
removing the repetition.
Remove an unnecessary string cast
Remove extra casts to long and double
Remove unnecessary casts to List
Add suppressions concerning genericts
Prepend Try Prefix to method with out parameter

This makes the naming of the method consistent with design patterns (and
other methods in the same library)