Various fixes related to text-indent, CSS order. Adds -cr-hint: strut-confined

[poire-z]

See individual commit messages for details.
Some additional notes:

• CSS: ensure selectors are applied in the order met discussed in Stylesheets: implement CSS selectors specificity #170 (comment).

• Fix getPageDocumentRange() on bidi text issue explained in Fix LVDocView::getBookmark() which could be slow or wrong #313 (comment)

• text-indent: some fixes, handle negative & hanging indent Issues detailed at CSS: Hanging indents are shifted to the right koreader#2857 (comment) . Closes CSS: Hanging indents are shifted to the right koreader#2857

• Text: fix: allow wrap on space around images Sample case:
  Before:
  
  After:
  

• (Upstream) Minor cleanup and ifdef wraps minor stuff picked from upstream in-progress merge of our changes Merged with KOReader fork of crengine buggins/coolreader#125, mostly related to what I added.

• CSS/Text: adds "-cr-hint: strut-confined" Will allow us to have a one-stop solution to publisher footnote links badly styled, and variable size inline images, that causes line-height oscillation in a paragraph:

        {
            id = "lineheight_all_normal_strut_confined";
            title = _("Enforce steady line heights"),
            description = _("Prevent inline content like sub- and superscript from changing their paragraph line height."),
            priority = -5, -- so other -cr-hint can override (this one has effect only on inline content)
            css = [[* { -cr-hint: strut-confined; }]],
        },

Before style tweak applied:

After:

(An inline image standalone on a line is not confined, as noticed at the bottom - the two other are reduced because they have a comma or a period after them.)

The main benefit (for me) is getting rid of badly styled footnote links (not even wrapped in <SUP>, that even the Ignore publisher line-height and the radical Ignore publisher font-size couldn't get rid of because of excessive vertical-align (one would have needed to look at the code and create a custom style tweak to get rid of that).
Before style tweak applied:

After:

• lvtextfm: avoid spurious spaces when hyphenating fixes this:
  
  when
  
  so we get the correct:
  

• lvtextfm: dont adjust space after initial quotation mark/dash Fixes this too wide space:
  

• lvtextfm: ensure page-break:avoid on inline-block and images is not required by specs, but will allow us to finally get nice gallery in Wikipedia EPUBs by having all the items inline-block, including a 100% caption, ensuring the captions is stuck on the same page as the first items:
  
  instead of the messy stuff we got with floats, screenshot in Enhanced block rendering (floats, collapsing margins...) #299.

• Fix internal/footnote links not working on some books fixed internal link not working when internal file names are percent-encoded (<a href="Author%20Title.html#fnt1">[1]</a>) - I sometimes had footnotes links not working, and always assumed it was the book that was badly made :|

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This change is 

[poire-z]

(To be bumped after coming up release.)

[poire-z]

Added a commit to fix some possible segfault I had a hard time reproducing - witnessed only 2 crashes, last one enough to notice it was indeed something flagged as OBJECT at wstart - with a Wikipedia EPUB while tweaking styles to try using display: inline-block, and reducing the window size to around 300x300...:

set view dimen {
    ["h"] = 328,
    ["w"] = 314
}
wstartflag0 wstart85 wend90
wstartflag0 wstart121 wend134
wstartflag8000 wstart0 wend5

0x00007fffe7dd21e2 in LVFormatter::processParagraph (this=this@entry=0x7fffffffb4f0, start=start@entry=0, end=end@entry=2,
    isLastPara=isLastPara@entry=true)
    at /space/kobo/koreader/base/thirdparty/kpvcrlib/crengine/crengine/src/lvtextfm.cpp:3213
3213                     int _hyphen_width = ((LVFont*)m_srcs[start]->t.font)->getHyphenWidth();

Related to changes from #320.

[poire-z]

Added more commits, top post updated with explanation and screenshots.