Expyriment 0.2.0 released

[Florian Krause]

Expyriment 0.2.0 has just been released!

New:

* Overall structure has changed quite a bit. There are now only 5
submodules (control, design, io, stimuli, misc). Things like
intialize() and start() are now in control. Constants are now in misc.
Each module has its own defaults now.

Changed:

* Adding blocks and trials will always add a copy. There is no
option for adding a reference anymore.
* Block and Trial IDs are now relative to where they are added.
For instance, two blocks can contain 10 unique trials each, but for
both blocks the trial IDs will go from 0 to 9.
* Adding stimuli will always add a reference!
* Stimuli have still an absolute unique ID

Fixed

* A variety of small bugs have been fixed