Add additional GroovyClassLoader tests

These tests specifically test for compliance with parts of JLS Section 5.
Fix spread-dot operator in user guide.
Merge pull request #451 from pledbrook/doc-patch-01

Fix spread-dot operator in user guide.
Correct javadoc references to Collect.collectEntries().
Merge pull request #452 from pledbrook/patch-01

Correct javadoc references to Collection.collectEntries().
Introduction to type checking section
Add operator overloading section to Groovy specification.
GROOVY-5957: groovydoc does not create links for non-fully qualified classes in same package
tweak typing doco wording
Merge pull request #455 from paulk-asert/groovy5957

GROOVY-5957: groovydoc does not create links for non-fully qualified cla...
Merge pull request #454 from pledbrook/doc-patch-02

Add operator overloading section to Groovy specification.
Documentation of simple rules for type checking assignments
GROOVY-3680: Cannot use Groovy class with @Bindable or @Vetoable in Java code: cannot find symbol for addPropertyChangeListener
Added documentation for list/map constructors
Documentation: Described principles of matching arguments to parameters
Fix failing test because the script ID may be different
Merge pull request #457 from paulk-asert/groovy3680

GROOVY-3680: Cannot use Groovy class with @Bindable or @Vetoable in Java...
GROOVY-3680: Cannot use Groovy class with @Bindable or @Vetoable in Java code: cannot find symbol for addPropertyChangeListener (add test)
Merge pull request #396 from candrews/MoreGroovyClassLoaderTests

Add additional GroovyClassLoader tests
GROOVY-3680: Cannot use Groovy class with @Bindable or @Vetoable in Java code: cannot find symbol for addPropertyChangeListener (improve test)