Bug fixes for Ubuntu Bionic support

Updated Ubuntu installation instructions with the PPA inclusion and m…

…inor updates to Launchpad packaging scripts for proper 18.04 LTS compilation.

SiQAD v0.2.1-hotfix1: fixed a crash where SiQAD GUI crashes upon New …

…document creation when a DB preview dot is on screen.

Swig Python headers now compiled by the root CMakeLists by default. F…

…or Linux, each Python simulation engine symlinks lib/siqadtools instead of relying on the user to install and update SiQADConnector separately. i686 cross-compilation have been added to make_everything_dev. Major edits to README.

Update README.md