Upgrade to latest version of guard and Coffeelint

Updated the guard and coffeelint dependencies to the latest version of each. These are working with no other changes.

In order to be able to develop the gem, however, I made one other change, placing `VERSION` in a separate file that the gemspec includes solely. This follows the structure that other gems follow, and fixes an error I was experiencing (using Ruby 2.0.0-p353):
```
There was a LoadError while loading guard-coffeelint.gemspec: 
cannot load such file -- coffeelint from
  /Users/robind/Dropbox/mlw2/guard-coffeelint/guard-coffeelint.gemspec:4:in `<main>'

Does it try to require a relative path? That's been removed in Ruby 1.9.
```
Could we drop the dependency version restrictions entirely for future proofing?

```ruby
spec.add_dependency 'guard'
spec.add_dependency 'coffeelint'
```