Decode message only if encoding is known

When python does not know the encoding of stdout, sys.stdout.encoding
is None.  Then calling decode(None) raises an exception.  We just
skip decoding when the encoding is unknown.

running_gradient object.

if you try to open a jpeg or png file.

dlib/all/source.cpp into their own .cpp files.  If so they will get a useful
error message.

visual studio.

sys.stdout.encoding instead of latin-1 in setup.py

Add pragma guards around deprecated auto_ptr to prevent GCC warnings

Fixes #67

Please use sys.stdout.encoding instead of latin-1 in setup.py.
This is necessary for non English OS.

Change relative path of configure files in CMakeLists.

Using CMAKE_PROJECT_DIR instead of CMAKE_SOURCE_DIR/../dlib
makes the build process more portable.