Fix LWUIT text editor focus issue.

We need to click twice to focus the text editor, because setVisible()
is called after setFocus().
Fix LWUIT key release issue.

`com.sun.lwuit.Display.keyReleased` is never been called which causes
`com.sun.lwuit.Form.keyRepeated` is invoked repeately.
Merge pull request #573 from PinZhang/pzhang/keyrelease-issue

Fix LWUIT key release issue.
Merge pull request #559 from PinZhang/pzhang/texteditor-focus-issue

Fix LWUIT text editor focus issue.
Implement password editor.
Fixed regression: the caret position lost.

caret position is lost in the case:
  - Edit TEXTAREA field, input some character
  - Edit PASSWORD field
  - Edit TEXTAREA field again, the caret lost.
Add testcases for PASSWORD editor.
Move libs/text_editor.js to midp/text_editor.js
Merge pull request #560 from PinZhang/pzhang/texteditor-password

Pzhang/texteditor password
Implement Graphics::drawSubstring native
Add DrawSubstring test
Update number of different pixels
Merge pull request #575 from marco-c/drawSubstring

Implement Graphics::drawSubstring native
Update number of max different pixels in DrawSubstringTest for Mac