Merge pull request #1 from nyue/master

Nicholas' contribution:
(1) Fixes : OSX port
(2) Addition : CMake configuration file for cross platform build
(3) Addition : Method to retrieve layout object
(4) Addition : Example to illustrate the use of layout object to query channel information more efficiently
renamed a file.
Created a cmake directory and moved the cmake build list into it.
Modified the cmake build process to allow users to provide their own FindILMBase.cmake and FindZLIB.cmake
-Added a rudimentary README explaining how to build.
-Removed build scripts that are subsumed by CMake.
-Added an object for managing generic metadata values.
-Added metadata support to prt_istream and prt_ostream
-Updated prt_ifstream and prt_ofstream to support the PRT v1.1 format described in http://www.thinkboxsoftware.com/krak-prt-11-file-format/
-Added another example program that writes files with metadata and displays all metadata in a file.
-Fixed a few bugs that popped up in the non-Windows build.
-Added the license text to the prt_meta_value.hpp file
Merge pull request #3 from ThinkboxSoftware/prtv1.1

PRT v1.1 format upgrades