Fix references to GSL on GitHub (imatix=>zeromq) in code

Author: jimklimov

Diff for: Vagrantfile

@@ -10,7 +10,7 @@ libpcre3-dev valgrind
 
 cd /vagrant
 if [ ! -d gsl ]; then
-    git clone https://github.com/imatix/gsl.git
+    git clone https://github.com/zeromq/gsl.git
 fi
 cd gsl/src
 make

Diff for: ci_build.sh

@@ -40,7 +40,7 @@ case "$BUILD_TYPE" in
     if ! ((command -v dpkg-query >/dev/null 2>&1 && dpkg-query --list generator-scripting-language >/dev/null 2>&1) || \
            (command -v brew >/dev/null 2>&1 && brew ls --versions gsl >/dev/null 2>&1)); then
         [ -z "$CI_TIME" ] || echo "`date`: Starting build of dependencies: gsl..."
-        $CI_TIME git clone --depth 1 https://github.com/imatix/gsl.git gsl
+        $CI_TIME git clone --depth 1 https://github.com/zeromq/gsl.git gsl
         ( cd gsl/src && \
           CCACHE_BASEDIR=${PWD} && \
           export CCACHE_BASEDIR && \

Diff for: zproject_travis.gsl

@@ -564,7 +564,7 @@ fi
 if ! ((command -v dpkg-query >/dev/null 2>&1 && dpkg-query --list generator-scripting-language >/dev/null 2>&1) || \\
        (command -v brew >/dev/null 2>&1 && brew ls --versions gsl >/dev/null 2>&1)); then
     cd "$REPO_DIR/.."
-    git clone https://github.com/imatix/gsl.git gsl
+    git clone https://github.com/zeromq/gsl.git gsl
     cd gsl/src
     make
     PATH="`pwd`:$PATH"