Add default value revert button and add assembly program export

• aa93829: Add button to revert public properties to their default value specified by their script. This only works on value type fields at the moment. The button is an arrow to the right of the property:
  
• e8e7ad3: Add support for exporting UdonSharpProgramAssets as UdonAssemblyProgramAssets so that you can export a program without needing U# as a dependency. This is intended for short and basic programs since the Udon assembly inspector is very lacking in its ability to draw public fields, and any updates to Udon's serialization are more likely to break these assets. In order to redistribute these packages you will need to include the assembly program this generates, as well as its serialized data asset that you can find by looking at the debug inspector for the assembly program.
  
• 3670343: Handle binary expressions better to avoid unnecessary copies
• c4a7191: Clean up the filesystem watchers more aggressively in attempt to avoid crashes that they may be causing
• 8ffa1ca: Fix error when compiling all scripts and you have a program asset with an unassigned source file