linetrack_covg_by_symbol: produce a TnT::LineTrack with coverage information for a...
In vjcitn/biocwk312: Workshop intro for Bioconductor 3.12.

produce a TnT::LineTrack with coverage information for a selected gene+radius

1	linetrack_covg_by_symbol(sym, bamf, radius = 0, ...)

`sym`	a gene symbol
`bamf`	a path to indexed BAM file
`radius`	numeric(1) defaulting to zero, upstream/downstream extra reach
`...`	passed to LineTrack, so can include color, etc.

if (requireNamespace("RNAseqData.HNRNPC.bam.chr14")) {
  f1 = RNAseqData.HNRNPC.bam.chr14::RNAseqData.HNRNPC.bam.chr14_BAMFILES[1]
  linetrack_covg_by_symbol("HNRNPC", f1, color="gray")
}