Change "source" to "." in autojump.sh

This makes the file more POSIX-compliant, which is useful in some OSs
that link /bin/sh to secondary shells for performance improvements
while still using bash as the default shell

Reference: https://wiki.ubuntu.com/DashAsBinSh

bin/autojump.sh

@@ -18,9 +18,9 @@ if [ "${shell}" = "sh" ]; then
 
 # check local install
 elif [ -s ~/.autojump/share/autojump/autojump.${shell} ]; then
-    source ~/.autojump/share/autojump/autojump.${shell}
+    . ~/.autojump/share/autojump/autojump.${shell}
 
 # check global install
 elif [ -s /usr/local/share/autojump/autojump.${shell} ]; then
-    source /usr/local/share/autojump/autojump.${shell}
+    . /usr/local/share/autojump/autojump.${shell}
 fi