add dialect study participants

[tjmahr]

It looks like we were doing a couple of studies under the umbrella of "Dialect". Some children did a DialectDensity set of tasks, many more did DialectSwitch tasks, and some did both. Thus:

I'm going to use Dialect to cover both. There is one child 402D who had received DialectDensity testing then 10 months later received a new batch of DialectSwitch and DialectDensity testing. I am going to archive 402D's earlier testing.

• [x] create studies in Study table
• [x] create entries in Child table
  • Except for the following aliases: 120L = 458D (double-check?)
• [x] create entries in ChildStudy table

[janroslynedwards]

Dialect density = Ruby's thesis

Dialect shift = study where children got RWL in both dialects.