Switch implementation to Python

Switch implementation to Python

The implementation is also a bit more powerful with respect to
parallelism and generated HTML output.

Following switches are available for build.py:

usage: build.py [-h] [--helenos-repository PATH] [--coastline-repository PATH]
                [--build-id ID] [--rss-url URL_WITH_RSS]
                [--resource-path RELATIVE_PATH] [--build-directory DIR]
                [--artefact-directory DIR]
                [--platforms PLATFORM1[,PLATFORM2[,...]]
                [--harbours HARBOUR1[,HARBOUR2[,...]] [--jobs COUNT] [--debug]

HelenOS integration build

optional arguments:
  -h, --help            show this help message and exit
  --helenos-repository PATH
                        HelenOS repository path
  --coastline-repository PATH
                        Coastline repository path
  --build-id ID         Build id (typically sequence number).
  --rss-url URL_WITH_RSS
                        URL of RSS for latest builds.
  --resource-path RELATIVE_PATH
                        Path where static web resources are stored (when
                        specified, the resources are NOT copied).
  --build-directory DIR
                        Where to build (space for temporary files).
  --artefact-directory DIR
                        Where to place downloadable files and HTML report.
  --platforms PLATFORM1[,PLATFORM2[,...]
                        Which platforms to build (defaults to all detected
                        ones; can be either machine specific "ia64/ski" or
                        architecture specific "ia64/*").
  --harbours HARBOUR1[,HARBOUR2[,...]
                        Which harbours to build (defaults to all detected
                        ones).
  --jobs COUNT          Number of concurrent jobs.
  --debug               Print debugging messages