Update CHANGELOG.md

correct extend description
info about `@import-once` removal
package.json keywords updated, formatting for readability, nothing else was edited.
Merge pull request #1230 from jonschlinkert/master

package.json edited
If the callback throws an error and imports are syncronous, let the error fall through to the calling scope.
Fix index on mixed units error. Fixes #1228
Fix extends when selector to add includes & and :extend is inline. Fixes #1227
ampersands in selectors using extend - more complex test
better support for attributes. Allow interpolation inside attributes. Fixes #1229
Allow variable interpolation in attributes everywhere that is sensible
beta 2 release
Do not normalize rootpath option as it is a URL. Fixes #1234
ENABLE max-line-len options support
Tidy up options
Fixes small typo in command prompt usage text
Merge pull request #1236 from editor/master

Fixes small typo in command prompt usage text
Add Less.js license to package.json
Merge pull request #1244 from theoreticaLee/master

Add Less license to package.json
Fixed issue cloudhead/less.js#1272

Local path should now work correctly.
Merge pull request #1273 from losnir/master

Fix for local paths