enable semaphore ci for old node tests

.travis.yml

@@ -2,12 +2,13 @@ language: node_js
 node_js:
   - "7"
   - "6"
-  - "5"
-  - "4"
-  - "0.12"
-  - "0.10"
-  - "0.9"
-  - "0.8"
+# note: travis has been acting up on old versions of node
+#  - "5"
+#  - "4"
+#  - "0.12"
+#  - "0.10"
+#  - "0.9"
+#  - "0.8"
 before_install:
   - "npm install -g npm@4.3.0"
   - "npm install -g mocha@2.x voc"

README.md

@@ -1005,6 +1005,8 @@ Worksheet File Format (From Lotus) December 1984
 
 [![Build Status](https://travis-ci.org/SheetJS/js-xlsx.svg?branch=master)](https://travis-ci.org/SheetJS/js-xlsx)
 
+[![Build Status](https://semaphoreci.com/api/v1/sheetjs/js-xlsx/branches/master/badge.svg)](https://semaphoreci.com/sheetjs/js-xlsx)
+
 [![Coverage Status](http://img.shields.io/coveralls/SheetJS/js-xlsx/master.svg)](https://coveralls.io/r/SheetJS/js-xlsx?branch=master)
 
 [![NPM Downloads](https://img.shields.io/npm/dt/xlsx.svg)](https://npmjs.org/package/xlsx)