Move GTest-Extensions.sln to root of repo
Move error formatting to seperate header file

Move formatting to StringErrorFormat.h
Inline mem leak checker function
Add gtest string formatting project
Add tests for gtest test predicate function

Gtest uses a predicate returning an AssertionResult to allow the user to
perform their own check and format the error message that they want.

Initial commit of a predicate function that conforms to gtest's
predicate signature.