Do not wipe out context.data, breaking @key, @index, etc in partials

[justinph]

This fixes the problems addressed in #22 and #41.

In the code without my patch, options.data is set to undefined, and then a few lines later we're merging all these objects, which causes the newly undefined options.data to wipe out any good object that we might have. As far as I can tell by tracing where options.data comes from and is used again, setting it to undefined again serves no useful purpose.

Big thanks to @yongtw123 for pointing me in the right direction in #22.

[nessthehero]

Can this pull request be merged? It fixes a pretty significant issue that limits a lot of functionality. It seems like this repo is a bit stale.

[jonschlinkert]

I think so, @doowb you ok with this?

[doowb]

Yeah looks good.

[jfrantzius]

Do I get it right that this will likely fix #22 ?
If yes, then it would be totally great if this fix got merged, as in our experience #22 is a blocker for using grunt-assemble with handlebars!

[justinph]

@jfrantzius: Yes, this should fix the issues with key, index, first, etc.

[doowb]

@justinph thanks for this fix. I've merged it in locally and will be pushing it up shortly.
I'll double check to see if this fixes #22 also. If not, we might have to bump Handlebars in assemble-handlebars.