Correct method comment in `HGMergeToolStartup >> #main:`

Rename "temporaryWorkingCopy" to just "workingCopy" thorough the code This is a preparation for removing use of temporary working copy altogether. The main problem is that it causes confusion, mainly among newcomers.

Use separate logic to detect classes whose copyright should be updated While `#shouldFileOutClass:` is conservative, i.e., may return true for classes that were not changed, (new) `#shouldUpdateCopyrightInClass:` should never return `true` in that case, the opposite (i.e., returning false in cases when class has in fact been changed) is unfortunate but somewhat acceptable.

Fix `HGChangeset >> #/' to work with obsolete changesets

Update .hgignore

Introduce `HGMergeTool` - a merge tool for Smalltalk/X source files `HGMergeTool` merge tool support another (Mercurial specific) invocation: ... -r REV LOCAL This can be used to cherry-pick changes to `LOCAL` file from revision `REV`. It automatically searches history for base revision to guide the (automatic) merge.

Introduce `SCMMergeTool` - a merge tool for Smalltalk/X source files This can be used by SCM (such as Mercurial or GIT) to merge Smalltalk/X source files (.st) instead of standard 3-way merge tools (such as `kdiff3` or `meld`). The advantage is that it operates atop of changesets, not on whole files.

Fix `HGTests >> #test_hgCommand_03_unix` for Python3 Use the same Python as the Mercurial's `hg` by reading `hg`'s shebang. This is to handle cases where Mercurial is using Python 3 but `python` command refers to (old) Python 2.

Make method's source local (i.e., in-memory) when filing-out class ...such as when commiting. This is a measure against source corruption when filing out to package directory (this is not yet supported, but this commit in a preparation for that)

Fix `HGStXTests >> #test_commit_nested_07a` The aim of this test is to check that changes are correctly shrunk only for commited classes / extensions. However, it incorrectly checked whether current changeset does not contain changes for class NOT commited. This is wrong - package commit may have touched other classes (like, adding copyright) but unless really commited, changes should not be shrunk for these uncommited classes! Interesting how long this flaw in this test when unnoticed. This has been uncovered by fixing / improving copyright update code.