Add region-based summary calculations for RNAP ChIP

[mikewolfe]

Added

• Added relative polymerase progression calculation to bwtools_query (http://dx.doi.org/10.1016/j.molcel.2014.02.005)
• Add the ability to smooth raw signals using convolution with a Gaussian or flat kernel.
• Add the ability to smooth raw signals using a Savitzky-Golay filter
• Ability to calculate the region-level spearman correlations for a set of samples in bwtools_query
• Add calculations of the traveling ratio (10.1016/j.molcel.2008.12.021)
• Add discovery of a local max within a region

Changed

• Output of bwtools_query is now compressed (gzip). File extension changed to .tsv.gz