RFR: 8351878: RichTextArea: copy/paste issues [v4]

[Andy Goryachev]

> Fixed several issues found in importing RTF text:
> 
> - charset translation (brought back removed code)
> - missing font size attribute
> - missing strike-through attribute
> 
> Also, HTML copy suffered from the following issues:
> 
> - incorrect font size
> - incorrect handling of boolean character attributes (bold, italic, etc.)
> 
> The charset issue was caused by my removal of the character decoder code present in the original JDK RTF parser/reader.  Why did I do that?
> 
> This PR does not add import of RTL paragraph attribute needed to align RTL text correctly.

Andy Goryachev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains nine additional commits since the last revision:

 - html
 - Merge remote-tracking branch 'origin/master' into 8351878.rtf
 - arabic
 - whitespace
 - test
 - strikethrough
 - missing code in attr set
 - font size
 - fixed arabic import

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1735/files
  - new: https://git.openjdk.org/jfx/pull/1735/files/f7834f61..63dbbb3d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1735&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1735&range=02-03

  Stats: 654 lines in 15 files changed: 584 ins; 31 del; 39 mod
  Patch: https://git.openjdk.org/jfx/pull/1735.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1735/head:pull/1735

PR: https://git.openjdk.org/jfx/pull/1735