Psychopy

We've fixed a number of further bugs with PsychoPy3, both in the online and local experiments.

Online fixes:

- data files were being saved with some duplicate columns and sometimes incorrect rows!
- there are various improvements to connectivity with pavlovia.org
- pavlovia.org itself is now able to deactivate and reactivate studies

Local application:

- (all) movie stimuli were crashing the program with MovieStim3 class!
- Joystick is working and has a Builder Component
- many smaller fixes

Fixes launch problems on MacOS in particular, but various minor fixes too

- Refactoring of PsychoJS to use ECMA6 *modules* system:

- e.g. `import * as visual from './lib/visual-3.0.0b3.js';`
- this is good for performance and means that the psychojs lib can be separated better into usable chunks
- we also moved to global declarations of variables using `var myMariable;` but this is done automatically for user variables (even from Code Components)

- added the "radio" style to Slider so we can create radio choice boxes
- lots of updates to the head mounted display tools

- FIXED:

- another packaging problem (esprima lib not being found on Standalone)
-

The Python2.7 release is still not packaging correctly on the MacOS so we only have a Python3 (default) release in this version.

Various bug fixes including:

- gamma table not "unset" correctly on windows 1972
- color-picker dialogs (right-click on a color parameter) were not setting stimulus colors due to returning a n RGBA value instead of RGB 1987
- further bug-fix to MovieStim3 unloading of sounds 1969

Fixing many further bugs!

Note that the 'default' Python being provided is now Python 3.6 but you can stick to Python2.7 by choosing that alternative standalone package below (labelled `_PY2` )

- Fixed problem with Image (Pillow) library not loading properly on some Macs
- Fixed problem with psychopy folder itself not being found when launching the PsychoPy3_PY3 standalone on Windows
- Turned off startup tips in the hope that sporadic beachballs on Py2 Mac package are fixed
- Fixed minor autoindent problem on Py3 installs for all platforms
- Fixed TextStim on Mac Py2.7 install (not finding configparser) although the fix was not to allow arabic_reshaper support on this package - use the Python3 or windows release if you need arabic text reshaping
- several small fixes and documentation for the new Slider stimulus

FIXED:

- several sync problems with pavlovia.org: [commit:1f0d8bcab](https://github.com/psychopy/psychopy/commit/1f0d8bcab50c1528291adb3a689e95f6e3bf7fc5)
- sync when an empty project already exists is now fine
- after creating the project, changing a file and repeating sync, it didn't detect the changed file
- sync to a project that has been deleted remotely now asks if you want to recreate the project
- better reporting of error if sync fails

- further fix to memory leak in MovieStim3 [commit:9d0c127d8](https://github.com/psychopy/psychopy/commit/9d0c127d8e6dfd6efba5f285bed93685980cd443)
- fix to PsychoJS output code: loops were not being compiled correctly [commit:6a8e700a3](https://github.com/psychopy/psychopy/commit/6a8e700a350b660b6f588c5b902b04a736b023d2)