Reserve sections of user guide to work on.
Set IDEA language level to 1.6 and JDK name to 1.8
Merge pull request #459 from pledbrook/doc-patch-03

Reserve sections of user guide to work on.
additional utility methods
GROOVY-6887: AutoClone issue with CompileStatic
Fixing Groovy5687Bug test case failing due to default locale producing 'em' as am/pm marker
Merge pull request #461 from traneHead/make-Groovy5687Bug-pass-independent-of-system-locale

Fix for Groovy5687Bug test case failing due to locale
GROOVY-6887: AutoClone issue with CompileStatic (additional tests plus tidy doco)
GROOVY-6889: clean up generated code when using @AutoExternalize with @CompileStatic
Merge pull request #462 from paulk-asert/groovy6889

GROOVY-6889: clean up generated code when using @AutoExternalize with @C...
Merge pull request #458 from paulk-asert/groovy6887

GROOVY-6887: AutoClone issue with CompileStatic
doco tweaks and tidy up for GROOVY-6889 and GROOVY-6887
GROOVY-6893: clean up generated code when using @EqualsAndHashCode with @CompileStatic
GROOVY-6894: clean up generated code when using @TupleConstructor with @CompileStatic