Updated README new branching
Travis to test stable branches only
Removed branch alias from composer.json
Cannot override field definition

        Close #127
BaseObject::Extract() dumps custom accessors.
Fix Pomm\Object\Collection::rewind()

Set the right property
Replaced "or" and "and" by || and &&
BaseObject::Extract() does't dump custom accessors

        Close #129

Conflicts:
	README.rst
	composer.json