classes.updates: Fix history-cleaning; logging tweaks

- Only check history if the update is a complex type (not `only_value`)
- Check that value/old_value is a dict before trying to use `in`
- Log the exception caught, when there is one
- Also log the listener/watcher name, when rejecting duplicate adds

eval_js: Less severe logs, longer delays

Improve Video Preview background contrast

Aaand, update the Feature Request / enhancement label

Update "bug" label for bug report issue template

Properties: Ignore overlapping context menu events

Use openshot.OPENSHOT_VERSION_FULL for version checking

Animated Titles: Don't add files if canceled

* Animated titles: Update progress for Blender 2.80

Blender 2.80 doesn't output "Part" messages anymore, so the frame
regexp was always failing, and the progress bar never updated.

This switches to detecting the final "Sce:" message for the scene, and
using it to update the progress bar.

* Animated Titles: remove unused close_window()

* Animated titles: Remove more slot methods

`blender_listview.py` contained a lot of slot methods of the form:
```py
def onRenderFinish(self):
    self.render_finished()
```
There's no real point to that, as `render_finished()` can simply be
decorated as a slot and connected directly. So, we do that instead.

* blender_listview: Remove codecs module

`codecs.open()` is documented as a wrapper around `open()` that uses
`errors='strict'` by default, so we can just do that ourselves.

Set scale=none on audio clips when splitting audio

Works around issue #2882, has_video = 0 clips show as black square
when scale is 'best fit'

Formatting, and lots of unused variables.

The name `property` is a builtin in Python 3, and while it's not a
reserved word (luckily, as this code wouldn't work), using a variable
named 'property' is still asking for trouble. So, this renames all
instances of `property` to `cur_property`.

This change doubles the retry timeout for JS calls made before timeline initialization to 100ms.

It also tracks the number of attempts for each delayed call, only logging (at reduced WARNING level) on the second retry. (On my system, this means eval_js no longer logs any messages on startup. Which is appropriate, since the brief iniitial retries it does perform are expected and unimportant.)

Update data from the default project too

Co-authored-by: NFrank Dana <ferdnyc@users.noreply.github.com>

Preferences: Avoid code duplication for browse type

Don't copy permissions when dup'ing template files (animated titles, still titles)

When application started default project loads where "display_ratio"
and "pixel_ratio" is present. Thus this data should be updated too.

Both the animated and still title editors make copies of template
files from the OpenShot installation, before modifying them. Those
files may be readonly, so use copyfile() instead of copy() to
duplicate them without the original permissions.

Fix a bug with the actionView_Toolbar checked state.

Fix a bug with the actionView_Toolbar checked state. When you start the application.

classes/ui_util: Remove unused variable

Co-authored-by: NTreOne <tre@tre.one>

WIP: Refactoring blender animations for 2.80 support

Fixing dissolve animated title (for sure one of the coolest)! Had to add new material nodes, fix some syntax, and change to emitting light.

Preferences: Raise max samplerate to 192kHz.