bump bower version

There was an error bowering snapjs, which upgrading bower fixed:

```
bower angular-snapjs#~1.4.1                     error Arguments to path.join must be strings

Stack trace:
TypeError: Arguments to path.join must be strings
    at path.js:360:15
    at Array.filter (native)
    at Object.exports.join (path.js:358:36)
    at GitHubResolver._checkout (/Users/jchris/code/mobile/ppnet/node_modules/bower/lib/core/resolvers/GitHubResolver.js:54:21)
    at /Users/jchris/code/mobile/ppnet/node_modules/bower/lib/core/resolvers/GitResolver.js:69:21
    at _fulfilled (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/p-throttler/node_modules/q/q.js:798:54)
    at self.promiseDispatch.done (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/p-throttler/node_modules/q/q.js:827:30)
    at Promise.promise.promiseDispatch (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/p-throttler/node_modules/q/q.js:760:13)
    at /Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/p-throttler/node_modules/q/q.js:574:44
    at flush (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/p-throttler/node_modules/q/q.js:108:17)

Console trace:
Trace
    at StandardRenderer.error (/Users/jchris/code/mobile/ppnet/node_modules/bower/lib/renderers/StandardRenderer.js:72:17)
    at Logger.<anonymous> (/Users/jchris/code/mobile/ppnet/node_modules/bower/bin/bower:111:22)
    at Logger.EventEmitter.emit (events.js:95:17)
    at Logger.emit (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/bower-logger/lib/Logger.js:29:39)
    at /Users/jchris/code/mobile/ppnet/node_modules/bower/lib/commands/install.js:35:16
    at _rejected (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/q/q.js:797:24)
    at /Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/q/q.js:823:30
    at Promise.when (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/q/q.js:1035:31)
    at Promise.promise.promiseDispatch (/Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/q/q.js:741:41)
    at /Users/jchris/code/mobile/ppnet/node_modules/bower/node_modules/q/q.js:557:44

System info:
Bower version: 1.3.3
Node version: 0.10.5
OS: Darwin 13.2.0 x64
```