Added support for collation

[sravanaravind]

Added support of collation which is new in version 3.4.

Used to specify language-specific rules for string comparison especially useful for case insensitive sorting.

Example:

Model.paginate({}, {
  collation: { locale: 'en' },
  leanWithId: false,
  page: page,
  limit: limit
})

[sirlancelot]

Any chance of this getting merged and a new version issued? This is important to enable case-insensitive sorting and searching.

Thanks!

[MzhouNiuniu]

麻烦合并谢谢