WFPC2 SMV code that treats PC differently

[stscijgbot-hstdp]

Issue HLA-1031 was created on JIRA by Steve Goldman:

In order to get more-consistent backgrounds in WFPC2 SVMs we may need to treat the PC differently/separately due to the different plate scales. While the code does loop through detector chips, it uses the same parameters for drizzling. A discussion will be needed to decide how to proceed with this issue.