New plugin to check that LUNs have the correct number of FC paths.

I have tested this against HDS Storage (2 x USP & HUS VM) and a 85 ESXi hosts (about 950 storage paths). Seems to work well. Though i should give it to the community. Craig.
Merge pull request #47 from craigawsmith/patch-1

New plugin to check that LUNs have the correct number of FC paths.