Leptonica 1.72 and /TP

[tofutim]

Hi, just a note when you get to it - or when I get the PR ready - when switching to 1.72, /TP (C++ mode) needs used as L_BUF_SIZE is no longer a #define but a static const, which VS does not like in /TC mode. It is a C99 thing that is supported by /TP.

The error will be things like

Severity Code Description Project File Line Error C2057 expected constant expression liblept-172 D:\Loqu8\OCR\tesseract-vs2015\liblept\src\classapp.c 101