Preseeds: change in base packages installed

[Emiliano Vavassori]

Please include within the preseeds for installation the following packages:

• ubuntu-restricted-extras (flashplayer, codecs for mp3 and other formats)
• geogebra
• gnome-search-tool
• ocrfeeder
• openshot
• freeplane
• gtk-recordmydesktop
• vokoscreen
• librecad (?)
• *-lts-xenial (LTS Hardware Enablement Stack from Canonical/Ubuntu), only on 14.04.

Also, please remove the following packages:

• webbrowser-app

[Emiliano Vavassori]

LibreCad is already included.

Opening issue #7 for HWE support and issue #8 for ubuntu-restricted-extras within client-pull-installation.