fixed missing Debian support in scripts/bootstrap.py
adjusted .gitignore to exclude scripts/tmp
changed os.fork idiom in script/bootstrap.py
improved scripts/start_db.py comment
added comment to scripts/start_db.py, added failure is OS is not matched
fixed messing up of /etc/apt/sources.list
fixed installation of postgresql 9.2 on Debian (package source and release check)
made scripts/bootstrap.py work on Debian, introduced osm_postgis_transform script (abtracted and shared code with bootstrap.py)