remove older tarballs from main

v4.0 commit, initial linked read support

Initial support for linked reads, such as those produced by the 10x
Genomics Chromium technology
Linked reads are supplied in the original SSAKE format, but the barcode
information is indicated by sequence following a single underscore "_"
Added a C. elegans linked read data assembly script in the test folder
Scaffolding options consistent with that of the LINKS scaffolder
SSAKE no longer sorts by/prioritizes high multiplicity reads for
assembly
Streamlined file names
Deprecated force-fill gap feature
Bug fixes

minor edits