3.5.1

Bugfixes:

Get a message when bedtools is installed instead of crashing without any message.
Always test if a bedgraph is tabix indexed without checking the extension
Fix a bug which was happening when operation or summary_method was used on bedgraph whereas the bedgraph had some missing intervals.
Enforcing version 15 of HiCMatrix. Version 14 had a bug concerning the application of the correction factors of cool files.