Adapted INI file for threading, not locking GUI

- Without the `threading` library, the GUI of DevWare gets locked up and
  we don't see what we're doing during acquisition.
  According to email from Bill@Aptina (Tue, 24 Jun 2014 16:09:17 +0000) we
  should split the acquisition part into its own function.
- Make output more concise and clear
- Harmonize all the rounding to two digits.
- functions for `fijioutput` and `SetExposureTime` now accept (optional)
  input parameters and have proper doc-strings
-