PATCH possibility of separately modify the inherited elements

[SLMitch]

I made a patch in order to modify 2 things :
* each items and triggers separately.
Indeed, several servers inherited of template UNIX, but trigger must not have the same configuration (for exemple le processor LOAD limit on a mono-processor and an octo-processor).

* Defaut time for display of graph : 2 hours
with 1 hour, php-gd make an picture where the curbs are discontinuous