Linker: Round 2

List of additions:
* Optionally ignore files which are contained in an __explicit dependency__
* __Perl Driver__
* __Temporary Workspace__
* __Makeflow is now a driver__ side effect: now the linker can start with any type of file
* __Dry run mode__ Show list of files and package structure without creating any files
* __verbose__ output
* __executable__ and __shared library__ driver
* detection of missing drivers