lib: Prefer abandonware/i2c

Change-Id: I09b302a0f30016a65b16433b7ad12138dfd0ac75
Relate-to: kelly/node-i2c#90
Origin: https://github.com/abandonware/bh1750
Relate-to: miroRucka#25
Forwarded: https://github.com/miroRucka/bh1750/pulls
Signed-off-by: Philippe Coval <rzr@users.sf.net>

bh1750.js

@@ -1,5 +1,11 @@
 var console = require('console');
-var i2c = require('i2c');
+
+var i2c = null;
+try {
+  i2c = require('@abandonware/i2c');
+} catch(err) {
+  i2c = require('i2c');
+}
 
 var BH1750 = function (opts) {
     this.options = opts || {