Support for instance tenancy in create_vpc
Add DHCP options filtering
Unit tests for create_vpc and get_all_dhcp_options
Convert existing VPC tests to AWSMockServiceTestCase, typos
Fix order of docstring args in get_all_dhcp_options
Merge pull request #1801 from mbarrien/vpc

Support VPC tenancy restrictions and filters for DHCP options. Fixes #1801.