Update changelog to 2.5.0

[ci skip]
Merge pull request #520 from sethkinast/master

Update changelog to 2.5.0
Fix the use of a multi-level object key (e.g. foo.bar) as the key for an index lookup inside non-self-closing tags.

Closes #521.
Merge pull request #522 from sethkinast/nested-key-array-access

Fix the use of a multi-level object key (e.g. foo.bar) as the key for an index lookup inside non-self-closing tags.
add more descriptive keywords to the package.json
Release v2.5.1
Merge branch 'master' of github.com:andyburke/dustjs
Change component.json to reflect new version and name.