'Theme & variations' exercise - change significance threshold

[csoneson]

• Note from the results output that the default significance threshold with DESeq2 is adj.P=0.1
• Figure out where this is set
• Change it to 0.05 instead
• (Much harder) challenge: figure out why the results are not necessarily the same as just setting a threshold on the adjusted p-value in the first set of results (since the independent filtering depends on the provided alpha)
• Variant: set a min logFC threshold to test an interval null hypothesis, and rerun the analysis. Again, figure out why the results are not the same as setting a threshold on the logFC after running the default test (of a point null hypothesis)