Pipe characters are not escaped, breaking tables

[vadcx]

Same issue as mzjp2/mdtable/issues/7, I will copy-paste the bug report below. Tested just now at https://csvtomd.com/

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Input CSV (LibreOffice):

Header,HeaderC2,Header C3
Normal line,another,And the last
if (OK && GREAT),it works,as expected
If (ouch || bad),oopsie,doopsie

Output Markdown (mdtable input.csv > output.md)

| Header           | HeaderC2 | Header C3    |
| ---------------- | -------- | ------------ |
| Normal line      | another  | And the last |
| if (OK && GREAT) | it works | as expected  |
| If (ouch || bad) | oopsie   | doopsie      |

You can see the || characters are not escaped to \|\| thus producing a broken result (pasted below). Simply escaping the characters as shown works on Github.

Header	HeaderC2	Header C3
Normal line	another	And the last
if (OK && GREAT)	it works	as expected
If (ouch		bad)