remove AOP aspects

See #34

XSLChain

See #33

XSL.applyTo()

Method XSL.applyTo() added, that allows to transform XML into plain text.

Dependencies upgraded

Some dependencies upgraded

XSL.with()

This version introduces a possibility to configure URIResolver for XSL transformations, using XSL.with() method and an instance of Sources interface. It is recommended to use ClasspathSources

XMLDocument.node() returns Document or Element

This version fixes a bug introduced a few versions earlier. Now XMLDocument.node() returns Document or Element depending on the situation.

Full immutability

This version makes all classes and interfaces in the library fully immutable, and annotated with @Immutable from jcabi-aspects

Extra synchronization in XSDDocument

Extra synchronized block in XSDDocument for thread-safety

XMLDocument is thread-safe

This version fixed concurrency problems with XMLDocument

More unit tests

No functional changes, just more unit tests