Replace temporary Files with tesseract stdin/stdout

[jgibbon]

This change introduces Tesseract.processStream() to simplify usage with build tools and reduce I/O. Tesseract.process() uses it but – except for an added return value – should remain compatible. (The tests pass, but I did not use it with options.config explicitly.) I also felt like adding another small test case.

[morenoh149]

could you fix the errors here? https://app.wercker.com/#buildstep/54c93225cc09f996373243af

[jgibbon]

I couldn't recreate the error locally, with a more or less recent version of tesseract. The version of tesseract on wercker does not seem to accept stdin at all (initially I tried the alternate parameters as you can see), so I'm afraid I won't be able to do anything to fix the errors there... I'm sorry if I wasted your time ;)

[morenoh149]

time to email wrecker :)

[ruudud]

bump

This would be highly appreciated. :+1:

Any help needed in making it work?