* Remove dependency on system fonts.

[harish2704]

• Fonts used for training should be part of training data
• Make it possible to render text using given ttf font file

[harish2704]

Found some hints here https://github.com/tmbdev/ocropy/blob/master/ocrolib/extras/cairoextras.py

[harish2704]

Pillow can render complex scripts if libraqm is available . This problem can be solved by using Pillow.

But this issue has to be take care https://github.com/harish2704/pottan-ocr/issues/12#issuecomment-538077411