Changed build system from SCons to WAF. * WAF is an old fork of SCons that is now for all intents and purposes a different build system. * Unlike SCons which requires a system install of the scons library to work, the entire WAF library is self-contained in a single 'waf' Python script provided with PARPG. * Build instructions are a little different from SCons - execute the local 'waf' script with the arguments 'configure install'. * To make a local install for testing, add the '--destdir=<directory>' option to make all files install under <directory> as a fake root (e.g. '--destdir=dev_install' would make WAF install all files under the 'dev_install' directory in the PARPG source). * Added a waf_paths.py WAF tool to set GNU-compatible installation path variables (i.e. PREFIX, EXEC_PREFIX, LIBDIR, etc.). These variables should be initialized to sane defaults on Windows, where GNU standards don't usually apply.