Add support for setting PkgConfig description via shortened property desc.
Add finding Poco via PkgConfig.
Add cmake support for FreeImage, KissFFT and Tess2.
Limit package names to not contain spaces and underscores (similar to debian).
Fix finding of multiple Poco libraries.
Rename package information file from version to package.json (similar to NPM).
Set our PkgConfig tool in the build environment for configure.