Merge branch 'nfontrod/nextflow-master' into dev

src/docker_modules/hisat2/2.0.0/Dockerfile

src/nf_modules/hisat2/indexing.config

src/nf_modules/hisat2/indexing.nf

src/nf_modules/hisat2/mapping_paired.config

src/nf_modules/hisat2/mapping_paired.nf

src/nf_modules/hisat2/mapping_single.config

src/nf_modules/hisat2/mapping_single.nf

src/nf_modules/hisat2/tests.sh

src/singularity_modules/hisat2/2.0.0/hisat2.def