Pharo port: add initial set of GT inspector extensions

Pharo port: correctly clear `#cli` property ...when CLI window is closed. This allows one to close CLI window and open it again.

Add a bunch of `#displayOn:` methods This commit adds a bunch of `#displauOn: aStream` methods, taking the implementation from VDB's presenters. This makes them available to other ports (e.g. Pharo)

Add `ports/3rdparty` to `.hgignore`

Compatibility: fix mutex creation Commit fdfe1a981 introduce portable mutex creation method but not all uses were actually updated. This commit updates these uses.

Update README.md with information on Pharo

Update README.md

Yet another fix `GDBCLICommand >> #operation` Commit 03a17952 attempted to fix `GDBCLICommand >> #operation` but somehow the fix in `Operations` list initialization was not commited. This commit adds these changes and hopefully really fix the issue.

Pharo port: do not track and kill (!) processes spawn during test Checking and terminating forked processes once testcase finished (worse before `#tearDown` of resources!) is a very stupid idea as it effectively breaks code that spawn long-running service processes (like LibGDB's even pump or LibUnix's process reaper). At the very least this behavior should be controllable by the test case, in other words a particular test case shoul be able to opt-out (or better, opt-in). But well, it is not hence this hack. Sigh. This is really not LibGDBs specific hack and probably should belong elsewhere but since I (JV) do know better place for it as of now and since above problem would almost certainly manifest when using LibGDBs, I put it here (until better place would be found).

Compatibility: use `#assert:description:` instead of `#assert:message:` ...as the latter does not exist (at least) in Pharo.