Add token validation to /run/import handler

[glensc]

When submitting data to /run/import add support for token GET parameter, it must match upload.token value from config.

Accompanying change in php-profiler:

• Add token support for upload saver php-profiler#17

[glensc]

This is a simple solution.

Ideally, there could be multiple tokens for different users.
Also, should do a constant-time comparison of the token to avoid timing attacks.

I'll leave those contributions up to the community.

[glensc]

I messed up with rebasing, and the changeset got to master branch already: dea75a5