Adding date1test to prep code

[jennifersmith203]

I noticed from Vale's pull request that date1test is not defined in the section about testing to start PrEP. I've added it in there, but also checked all the different testing places and there were a few other things that weren't consistent. So I've tried to make them all the same - so every time testing happens, I've put all the various testing-related variables (where applicable) in this order:

tested=1;  tested_specific_reason=1;
if ever_tested ne 1 then date1test=caldate{t}; ever_tested=1; dt_last_test=caldate{t}; 
np_lasttest=0; newp_lasttest_tested_this_per=newp_lasttest; newp_lasttest=0;

There's no rush to merge this but perhaps we can discuss together. Or if you have time, please could you have a look through and check that they make sense? In particular, I can see that the second line won't be relevant when someone is explicitly retesting so I have omitted in some places, but is the last line needed every time someone tests?

[ValentinaCambiano]

Hi Jenny,

Thanks for doing this, wondering whether we should have a variable as well testing as part of the general testing in the general population, we can discuss. I think we need to decide how to refer to it is it provider initiated tetsing and couselling? or facility-based testing?

[andrew-phillips-1]

yes I don't think we are currently able to distinguish between those two types of testing