Bowtie: add singularity files and add signature for singularity build

src/singularity_modules/BEDtools/2.25.0/build.sh

 #/bin/sh
 sudo singularity build --force bin/bedtools:2.25.0.sif src/singularity_modules/BEDtools/2.25.0/BEDtools.def
+singularity sign bin/bedtools:2.25.0.sif

src/singularity_modules/BWA/0.7.17/build.sh

 #/bin/sh
 sudo singularity build --force bin/bwa:0.7.17.sif src/singularity_modules/BWA/0.7.17/BWA.def
+singularity sign bin/bwa:0.7.17.sif

src/singularity_modules/Bowtie/1.2.2/Bowtie.def

+Bootstrap: docker
+From: ubuntu:18.04
+
+%labels
+MAINTAINER Laurent Modolo
+
+%post
+BOWTIE_VERSION=1.2.2
+SAMTOOLS_VERSION=1.7
+PACKAGES="bowtie=${BOWTIE_VERSION}* \
+samtools=${SAMTOOLS_VERSION}*"
+
+apt-get update && \
+apt-get install -y --no-install-recommends ${PACKAGES} && \
+apt-get clean
+
+%environment
+export BOWTIE_VERSION=1.2.2
+export SAMTOOLS_VERSION=1.7
+
+%runscript
+exec /bin/bash "$@"

src/singularity_modules/Bowtie/1.2.2/build.sh

+#/bin/sh
+sudo singularity build --force bin/bowtie:1.2.2.sif src/singularity_modules/Bowtie/1.2.2/Bowtie.def
+singularity sign bin/bowtie:1.2.2.sif

src/singularity_modules/UrQt/d62c1f8/build.sh

 #/bin/sh
 sudo singularity build --force bin/UrQt:d62c1f8.sif src/singularity_modules/UrQt/d62c1f8/UrQt.def
+singularity sign bin/UrQt:d62c1f8.sif

src/singularity_modules/sambamba/0.6.7/build.sh

 #/bin/sh
 sudo singularity build --force bin/sambamba:0.6.7.sif src/singularity_modules/sambamba/0.6.7/sambamba.def
+singularity sign bin/sambamba:0.6.7.sif