(Fact-613) Rename 'processor' module to 'processors'

This commit renames the 'processor' module to 'processors',
which is more consistent with the 'processors' structured
fact and the directory structure which was created for it.
(FACT-613) Remove interaction with internal loader in legacy processor fact

This commit removes the call to facter.collection.internal_loader.load
in the legacy processor fact, which was redundant with the call to
Facter.value.
(FACT-613) Update confine blocks in legacy processor facts

This commit updates the confine blocks in legacy processor facts
to confine based on the existence of the 'processors' structured
fact, rather than on kernel.
(FACT-613) Rename keys of processors structured fact

This commit updates the naming of keys within the processors
structured fact to reduce redundancy.
(FACT-613) Convert 'models' key of processors structured fact to array

This commit changes the 'models' key within the processors structured
fact into an array. Previously, the key was a hash which was used
to support the legacy dynamic 'processorX' flat facts. With this
change, the flat fact itself handles its naming based on the index
number of a processor in the array.
(FACT-613) Stylistically update processor facts
Merge pull request #737 from whopper/processors_fixup

(FACT-613) Structured processor fact maintenance