Hacked includes to try to work around a build failure on Trusty

When I tried to pip2.7 install tesserpy on Ubuntu Trusty, with libtesserpy-dev installed, I got this error:

    tesserpy.cpp:632:9: error: aggregate ‘STRING value’ has incomplete type and cannot be defined
      STRING value;
             ^

The attached PR gets rid of that error, and tesserpy seems to install properly (though I don't know enough about the library to test it properly...)