naming of optional dependency packages

[nsheff]

It bothers me a little that the backend optional dependency package is named db-backend, because python packages and modules can't have hyphens in them.

It works to have the hyphen in there, since this isn't a module or package... but still, it caused me some problems because when it wasn't working, I thought it might be due to that.

I think it would be better to have a one-to-one correspondence between optional dependency name and module name. Since we call the module dbbackend in the code, I think the optional dependency name should correspond, and be dbbackend.

what do you think?

[donaldcampbelljr]

I implemented this change in dev last week:
81ca9f2

[nsheff]

thanks.

[donaldcampbelljr]

Closed via #92