New subprocess implementation and multiple fixes

Changes:
* Running processes now uses new implementation that is more resilient
  against stucked programs and reports output as soon as it happens
* opkg-wrapper: added possibility to ignore custom feeds
* pkgupdate: consider set root directory when looking for default entry
  config
* Add additional reported states to pkgupdate

Cleanups:
* dropped base.lua as it is part of distribution not updater it self now

Fixes:
* Fix l10n and list settings error when there is no relevant section in
  uci config
* Fix root directory to be used as absolute path because otherwise use
  of this variable broke with changed directory
* opkg-wrapper, localrepo: take in consideration root directory
* Fixed some warning that were failing tests