UI work for "ExampleList" displaying custom rules

PersistAndSplitListUI.diff patch does UI related things for working with custom rules. (I'll look at setting ExampleList's editor read-only when I get some time).

The patch from issue 14 should be applied first

• ExamplesList.java

** add splitter for list and editor pieces

** persist size/location/split-divider

• FindDuplicatesRefactoringPanel.java

** persist knownPattern or customPattern selected
I introduced a package private version of
"setPattern" with a "overrideSettings" argument

** Use JEditorPane (not JTextArea) and do setContentType

ExamplesList uses JEditorPane; FindDuplicatesRefactoringPanel uses
JTextArea. I had to make FindDup... a JEditorPane (to avoid Exception
about needed StyledEditorKit) so I could do setContentType to get some
jVi functionality. In ExamplesList there is
{{{
pattern.setContentType(org.openide.util.NbBundle.getMessage(
ExamplesList.class, "ExamplesList.pattern.contentType"));
}}}
which seems strange to me (out of a bundle). I used
{{{
pattern.setContentType(getMyTextContentType());
}}}
where getMyTextContentType is a static method that could be shared.

BTW, I ended up editting the .form and guarded area to change JTextPane
to JEditorPane because I couldn't figure out how to replace the text
component in the scroll pane without blowing away layout related.

Update this patch to fix a couple of bugs

1. set ExampleList text field to read only
2. in FindDupRefPan, maintain LRU order of pattern read from prefs

NOTE: the patch has the same name, don't see a way to invalidate the prevous one

following for the latest patch: /jackpot30/ $ sum /erra/Desktop/PersistAndSplitListUI.diff 50047 61