as being signed rather than unsigned.

Added guards so dlib::async code isn't pulled in when using old versions of visual studio (since they don't support c++11).

in the file names to make it so there won't ever be any name conflicts
in the cropped images.

now the output images are always the same dimensions but the objects scale changes.

processes since sometimes stdin was closed in some environments.  Also cleaned
up the code a little bit.

complain about this (and it's technically not allowed in C++).

Added clamping on conversion functions.

* Shape predictor trainer optimizations

* Fixed performance leak in single thread mode & made VS2010 support

are directly the arguments of a mex function.  This way, we avoid the problem
of dlib::matrix objects being created in other threads that internally call
into matlab and mess it up (since matlab is not thread safe in any sense).