Do not set indeterminate state on progress bars

The progress bars for installing third-party libraries were initialized
with indeterminate mode.  This results in a pretty *I'm doing something*
animation which slows down the system.  Furthermore, the progress bars are
not even visible, so there is no need for any animation.

Fixes processing#1561
Merge pull request #2451 from davidfokkema/fix-cpu-usage

Do not set indeterminate state on progress bars