optional element interface
draft version of the option<t> implementation
fixed bug in composite iterator
last function is really optional (not lazy, however)
removed IteratorToIterator
removed ArrayIterator
removed composite function
removed bunch of redundant functions and interators
code cleanup
slice iterator shouldn't evaluate everything
Merge branch 'master' into feature/optional-elements
pre-filter selector descendants
support for comma in selector
jcr queries supports comma
simplified nondegenerated function
added CHANGELOG
Merge branch 'feature/optional-elements'
updated version number in the README
added 1.3.1 version to the CHANGELOG