Added the actual implementation for ReplaceComponentItem.cs. Still having some trouble testing this, but checking in to keep Quirijn happy. :-)

Signed-off-by: Dominic Cronin <dominic.cronin@gmail.com>
Merge branch 'master' of https://github.com/DominicCronin/T-cubed
Merge branch 'master' of https://github.com/DominicCronin/T-cubed