Update package.json (Update handlebars version, for possibility to use decorators)

[AGvin]

According new updates in handlebars, now we can use decorators.

Doc: https://github.com/wycats/handlebars.js/blob/master/docs/decorators-api.md

Example of default (inline) decorator: https://github.com/wycats/handlebars.js/blob/master/lib/handlebars/decorators/inline.js

Example of code (in test case): https://github.com/wycats/handlebars.js/blob/master/spec/regressions.js

[AGvin]

As I saw, now exists PR #16
But as I think, handlebars must be updated to latest version

Additionally, added possibility to set handlebars instance at initialization of gulp-compile-handlebars.

According this changes, we can't get handlebars instance from plugin, but it can be provided as option at plugin execution.

[kaanon]

This one is a breaking change. I'll need to put this in a different version

[artem-malko]

Is there any news about this feature?