fixed mobylette load error in Rails5.0.0.rc1

[wenweih]

The error message is:

`rescue in block (2 levels) in require': There was an error while trying to load the gem 'mobylette'. (Bundler::GemRequireError)
Gem Load Error is: uninitialized constant ActionView::FileSystemResolver

need to require specify rails module:require 'action_view/template/resolver'

16-5-17 update:

before_filter is deprecated and will be removed in Rails 5.1. Use before_action instead

[garlou]

What is wrong with this PR?

[verymilan]

Why is this still open? o.O

[ikuwow]

https://github.com/tscolari/mobylette/pull/53/files#diff-9f99796b5fe9f9971c8e8df2a2ce7414R36 it removes annoying deprection warning: DEPRECATION WARNING: before_filter is deprecated and will be removed in Rails 5.1. Use before_action instead. (called from block in <module:RespondToMobileRequests> at ... in rails 5.0.3

Please merge it!