DATA VIZ: Fix bugs, incorrect string and null displays

[lumos309]

• Fixed null slash in head of pair not displaying
• Fixed wonky arrows like this
• Added quotation marks around strings (VIZ: draw_data improvements  #475)
• Fixed incorrect viewport sizing for drawings with functions

[coveralls]

Pull Request Test Coverage Report for Build 3374

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 36.883%

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Totals
Change from base Build 3372:	0.0%
Covered Lines:	2681
Relevant Lines:	6503

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💛 - Coveralls

[martin-henz]

Still not quite right: Now numbers appear as strings:

[lumos309]

Still not quite right: Now numbers appear as strings:

Oops! Fixed now.

[geshuming]

I'm getting Line 2: ReferenceError: is_array is not defined from this snippet:

const a = (pair(1, 2));
draw_data(pair(a, a));

[geshuming]

Can you add the relevant functions that were removed from this commit

[martin-henz]

Checked the recent bugs: all working.

Also canvas size is adapting to the size of the drawing.

[geshuming]

Some more tests I performed...

const ebst = make_empty_tree();

const bstll = make_tree(4, ebst, ebst);
const bstlr = make_tree(5, ebst, ebst);

const bstrl = make_tree(6, ebst, ebst);
const bstrr = make_tree(7, ebst, ebst);

const bstl = make_tree(2, bstll, bstlr);
const bstr = make_tree(3, bstrl, bstrr);

const bst = make_tree(1, bstl, bstr);


draw_data(bst);

results in:

Note the non-uniform padding of the image.

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const ist = list(1, "abc", x => x, pair(1,2), null, "superlongstring", 1234567890);

draw_data(ist);

results in:

Note the *1 where "superlongstring" is supposed to be.

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The data viz component doesn't resize together with the parent component (see below).

It seems like the component has a fixed window height? If the window is overflowed, it would result in 2 scroll bars!!!

[geshuming]

Merging due to regression issues