updated Changelog in anticipation of 0.7
# Changelog
+## Version 0.7.0 (September, 2018)
+This is a major, API-breaking release. It introduces a large number of new features, bug fixes, and improvements.
+
+API-BREAKING CHANGES:
+* A number of entities (or keywords) have been renamed to align more closely with the BIDS specification documents:
+ * 'type' becomes 'suffix'
+ * 'modality' becomes 'datatype'
+ * 'acq' is removed (use 'acquisition')
+ * 'mod' becomes 'modality'
+* The following directories are no longer indexed by default: derivatives/, code/, stimuli/, models/, sourcedata/. They must be explicitly included using the 'include' initialization argument.
+* The grabbids module has been renamed to layout and BIDSLayout.py and BIDSvalidator.py are now layout.py and validation.py, respectively.
+* The BIDS validator is now enabled by default at layout initialization (i.e., `validate=True`)
+* The `exclude` initialization argument has been removed.
+
+NEW FEATURES:
+* File metadata is now searchable (use `BIDSLayout.search_metadata()`)
+* A new BIDSFile wrapper provides easy access to `.metadata` and `.image`
+* HRF convolution is now supported via bundling of nistats' hemodynamic_models module; convolution is handled via the `convolve_HRF` transformation.
+
+MINOR IMPROVEMENTS AND BUG FIXES:
+* Specifying 'derivatives' in a paths specification now automatically includes 'bids' (#246)
+* Variable loading via load_variables can now be done incrementally
+* Expanded and improved path-building via `layout.build_path()`
+* `get_collections` no longer breaks when `merge=True` and the list is empty (#202)
+* Layout initialization no longer fails when `validate=True` (#222)
+* The auto_contrasts field in the modeling tools now complies with the BIDS-Model spec (#234)
+* Various minor internal improvements
+
## Version 0.6.5 (August 21, 2018)
* FIX: Do not drop rows of NaNs (#217) @adelavega
