Nanovar

* Fixed file type detection (Thanks to jiadong324, https://github.com/cytham/nanovar/issues/9#issuecomment-626579853)
* Fixed negative coordinates in VCF

* Changed version import approach in setup.py
* All SV classes except deletions now undergo secondary analysis by hsblast alignment
* Allowed clustering of Nov_Ins to other SV classes
* Added depth of coverage information in VCF header
* Fixed SV index duplications
* Added BND limitation in README.md
* Removed "number_of_maps" from condfidence score equation in nv_nn.py to capture SVs consisting repetitive elements

* Fixed Exception bug in nv_cluster.py (Thanks to jiadong324, https://github.com/cytham/nanovar/issues/9#issuecomment-609146494)
* Added mincov filter early in nv_cluster.py for faster computation
* Re-ordered writing of debug files in nv_characterize.py
* Fixed novel insertion length bug in nv_cluster.py
* Fixed duplication coord directional issue in nv_cluster.py
* Size correction for INV and DUP SVs in nv_vcf.py
* Add 400 bp buffer to in-built gap files (0-based)
* Fixed bug in breakend record in nv_vcf.py
* Added output table in README.md

* Fixed deletion sv length threshold and double negative bug in nv_vcf.py
* Changed relative input paths to full paths in nv_vcf.py
* Fixed left and right coord allocations in nv_cluster.py
* Corrected nv_input.py typo
* Corrected README.md typo

* Fixed missing nanovar script

* Upgraded model (ONT (Guppy) - v1, pacbio (CLR or CSS) - v1)
* Modified normal read breakpoint buffer from 400 to 100 to include shorter alignments as breakend-opposing reads
* Survey invalid symbols in contig ids and ignore reads mapping to these contigs (Thanks to Simone, https://github.com/cytham/nanovar/issues/6#issuecomment-595851018)
* Added a new debug file 'detect.tsv'
* Removed blast table intermediate file when not debugging
* Added limitation section in README.md