calc.cfb: Calculate CFB
In RVA: RNAseq Visualization Automation

This function calculates the change from baseline.

1	calc.cfb(data, annot, baseline.flag, baseline.val)

`data`	Dataframe with subject id, annotation flag, gene id and cpm value (from count tables) columns.
`annot`	A long-format dataframe with any pertinent treatment data about the samples. The only required column is one titled the `sample.id` value with values matching the column names of sample IDs in `data`. Additional columns can contain information such as treament compounds, dates of sample collection, or dosage quantities.
`baseline.flag`	A character vector of column names. These columns in `annot` contain the values to compare across.
`baseline.val`	A character vector of values. This vector must be the same length as `baseline.flag`, and the value at each index must represent a value from the column given by the corresponding index in `baseline.flag`.