This commit reverts part of f73f8ee84 which introduced an issue when
resizing a subcomponent with an attached OpenGLContext.

More details of the issue can be seen at
https://github.com/juce-framework/JUCE/issues/914.

See BREAKING-CHANGES.txt for more details.

This fixes warnings that are emitted when building with the `-analyze`
flag enabled.

Previously, the following plugins were causing issues when hosting their
editors:

- Softube plugins. I used Saturation Knob for testing, which crashed when
  deleting the temporary parent view.
- KORG Gadget series, which displayed a black screen after the temporary parent
  view was deleted.
- FabFilter Pro-C, which displayed at the wrong scale when opened on a
  retina display.

The default main JuceActivity for JUCE apps calls appNewIntent() in its onNewIntent() implementation which is defined in juce_gui_extra. This commit moves the implementation into juce_gui_basics.

Also added support for selectAll: selector forwarding in NSViewComponentPeer