Added reporting on execution at the end of QMiner.
JsonVal returns strings by reference when possible.
Fixed calls to TStrIn when used internaly and does not require copy of the buffer. Much faster.
Merge branch 'TStr' of github.com:qminer/qminer into TStr
Fixed reporting in stopwatch
Merge pull request #125 from blazf/TStr

Fixed TStrIn, minor changes
tests
Merge branch 'TStr' of https://github.com/qminer/qminer into TStr
int parsing didn't check for overflow before