add change locale API
Merge branch 'master' into multi-language
Merge branch 'master' into multi-language

Conflicts:
	errors.go
Merge branch 'master' into multi-language
add IsPreferMarkdown to Entry data
Merge branch 'master' into ck-editor
Merge branch 'master' into ck-editor
Merge branch 'master' into ck-editor
add choose editor APIs
Merge branch 'master' into ck-editor
delete Comments
Merge branch 'ck-editor'
remove validate
revert ck editor
Merge branch 'master' into multi-language

Conflicts:
	api.go
Merge pull request #13 from theplant/multi-language

Multi language Switching
update group data
update SelecteGroup data
Update for group sidebar items