Text selection does not work occasionally

[orionlee]

This is a follow-up on #36 .

After #36 is resolved, text selection works most of the time, but not always.

At times, selection on certain paragraphs will not work.

• It can usually be fixed by leaving story screen and resume back. Simply scrolling up / down won't help.

[orionlee]

Diagnosis:

• somehow after splitting story HTMLs into multiple TextViews (in StoryChapter, occasionally the text in some TextViews can't be selected.

      mTextSpans = Parser.split(HtmlParser.fromHtml(mTextHtml));

The conclusion is reached after eliminating a few other sources:

1. replace the custom JellyBeanSpanFixTextView with platform's TextView: no change.
2. replace the custom html-to-span parsing HtmlParser.fromHtml with platform's Html.fromHtml: no change.
3. remove splitting (i.e., entire chapter html in one big span): text selection works consistently.