Add more information to build and implement text module to README.md

[JieunKim4578]

• add sudo ldconfig and tesseract -v to make sure that tesseract is built successfully

• Fix unused url to download eng.traineddata from tessdata 3.04

Related issue #2435

This pullrequest changes

1. add sudo ldconfig tessract -v

2. Fix unused url to download eng.traineddata correctly

[alalek]

Thank you for contribution!

Tesseract installation instruction (Linux, Mac) The instructions below are for those who wants to build tesseract from source.

I would prefer to remove them completely:

• There is no problem to install tesseract from system package managers (including recognition data)
• These instructions of external project are not tested and become outdated too quickly.
• It is better to refer on documentation of tesseract project for actual build instructions from source.