Version 0.55.0

Fragment updates

Unpoly now detects when an [up-target] with multiple selectors would replace the same element multiple times. In such a case the target selector will be shortened to contain the element once.
Unpoly now detects when an [up-target] with multiple selectors contains nested elements. In such a case the target selector will be shortened to only contain the outmost element.

up.util.uniq() now works on DOM elements and other object references.
New experimental function up.util.uniqBy(). This function is like uniq, accept that the given function is invoked for each element to generate the value for which uniquness is computed.
Changes to utility functions that work on lists (up.util.each(), up.util.map(), up.util.all(), up.util.any(), up.util.select(), up.util.reject()):
- List functions now accept a property name instead of a mapping function:
```
users = [{ name: 'foo' }, { name: 'bar' }]
up.util.map(users, 'name') // ['foo', 'bar']
```
- List functions now pass the iteration index as a second argument to the given function:
```
users = [{ name: 'foo' }, { name: 'bar' }]
up.util.map(users, function(user, index) { return index }) // [0, 1]
```