Add datetimetz module for timezone information in date display

Allow multiple comma seperated timezones

Handle click to cycle through configured timezones
Example:
```
bumblebee-status -m datetimetz -p \
datetimetz.timezone=\
"Australia/Sydney,Pacific/Auckland,America/Los_Angeles"
```
Added dependencies to travis config

themes/icons/awesome-fonts.json

@@ -6,6 +6,9 @@
 	"date": { "prefix": ""	},
 	"time": { "prefix": "" },
 	"datetime": { "prefix": "" },
+	"datetz": { "prefix": ""	},
+	"timetz": { "prefix": "" },
+	"datetimetz": { "prefix": "" },
 	"memory": { "prefix": "" },
 	"cpu": { "prefix": "" },
 	"disk": { "prefix": "" },