Merge pull request #776 from ogarcia/doc

Update requirements list in the documentation

Author: darealshinji

screenfetch-dev

@@ -23,7 +23,9 @@
 # to put forth suggestions/ideas. Thank you.
 
 # Requires: bash 4.0+
+#           bc
 # Optional dependencies: xorg-xdpyinfo (resoluton detection)
+#                        xorg-xprop (desktop environment detection)
 #                        scrot (screenshot taking)
 #                        curl (screenshot uploading)