Project name should implicitly fill as expected in experiment spreadsheets

[ressy]

In the experiment spreadsheets the Contacts and Tasks columns are effectively "filled" across rows for the same project (since they're actually attributes of the project, not the sample) but the Project column isn't, which leads to counterintuitive behavior when looking at the spreadsheet.

For example this will group the three samples under project "proj," trim them, and email the results as expected:

Sample_Name	Project	Contacts	Tasks
S001	proj	email@example.org	trim
S002	proj
S003	proj

But this will only include S001:

Sample_Name	Project	Contacts	Tasks
S001	proj	email@example.org	trim
S002
S003

This could be handled by either actually filling all columns "downward" for empty entries when loading the spreadsheet, or just during project setup, keeping the experiment rows as they are now.