Stub EnvrionCapability.SupportsAddressAllocation methods
Rename method
Test stub methods
Typo fix
Add joyent test
Merge pull request #919 from voidspace/supportsaddressallocation

Add stub EnvrionCapability.SupportsAddressAllocation methods

Add stub EnvrionCapability.SupportsAddressAllocation methods that returns false for all providers. This is a precursor to using this for maas to detect support for static ip address allocation.