[Big one]: Rationalized build infrastructure to just two requests - writeTex and compileTex

The changes here work in conjunction with changes in gutenberg makefiles
and changes in the Rails app. These latter will be committed separately

If it all works, then we wouldn't need 3 separate requests - buildQuiz,
buildTestpaper and processWorksheet. Java need only write the bare
minimum information for Make to take over
Minor changes here and there in Mint + tabs removed
Create a soft-link to the problem folder in mint/

And reference this link in the e-mail sent to bugs@gradians.com
Sanity check added in method errorOut