Append filename to error when parsing Tonel file ...as a courtesy to the user. Makes debugging easier, especially after incorrect merge.

Tonel: only load files ending with `.class.st` and `.extension.st` This prevents tonel to load some git merge artifacts (line when in the middle of interactive rebase or similar).

Log errors occured during class initialization.

Remove unused Squeak UI code

Transform snapshot just before loading into / just after creating from ...Smalltalk/X. When loading, this commit delays use of snapshot transformations till the very last point just before loading. When creating snapshot from code in image, snapshot is transformed very early on. This sort of makes sense and helps when one wants to load code into RING2 model or similar. In this case, transformation is unwanted.

phase-divergent update to b2f0322f5c53: Use separate porters when writing out / reading in snapshots

Use separate porters when writing out / reading in snapshots

Strip Smalltalk/X C++ style namespace prefix when writing package This is to improve ability to interchange code.

Fix `MCStXPackageInfo` to not include extensions placed in normal protocols ...as norm in Smalltalk/X and not in special star-prefixed ones as it's used in Squeak / Pharo.

Do not sort class variables and pools when creating a class ...as the order may have some meaning to user and doing it automagically only causes noise in text diffs (for example, when using Tonel and git).