Fix enter key bug.
 - wrap startContainer's inline top with paragraph instead of startContainer.
exclude paragraph on wrapBodyInlineWithPara.
Fix bug insertParagraph, insertNode on cell.
 - Document level: bodyContainer > block > inline
Merge pull request #565 from HackerWins/bugfix/wrapBodyInlineWithPara

Bugfix/wrap body inline with para
Wrap body inline with para.
 - add fullycontains options at `range.nodes`.
add comments.
Merge pull request #570 from HackerWins/bugfix/wrapBodyInlineWithPara

fix wrapBodyInlineWithPara bug.
Update version 0.5.6 and test files.
Merge pull request #571 from HackerWins/develop

Fix enter key bug.