When inserting a line into an output window, we have to delay appending
the line feed character. Otherwise strange visual effects appear under
certain circumstances.
I have no idea why.

Fixes: QTCREATORBUG-24411
Change-Id: If8842ae4d9db36d514996b1f34dcca0432fafbfc
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

We'd like to create more useful tasks from compiler output, that is, try
harder to identify consecutive lines that refer to the same issue and
create one task for them, rather than one for each line. In such
"aggregate" tasks, the first line will not necessarily carry the main
information. Therefore, we make it explicit what this main information
is by introducing a dedicated summary member.
Also streamline the font handling for compile tasks.

Change-Id: I933f2643a13c710dab1ab548c56669b129026eb5
Reviewed-by: hjk <hjk@qt.io>

Now only one piece of code needs to be written to both linkify output in
an output pane and create tasks for it in the issues pane.
The calling sites are also simplified. For instance, until now, build
steps had to feed their output parsers manually and then push the
created tasks up the signal stack in parallel with the actual output,
which the build manager relied upon for cross-linking the output pane
content. Afterwards, the output would get forwarded to the formatter
(and parsed for ANSI escape codes a second time). In contrast, a build
step now just forwards the process output, and task parsing as well as
output formatting is done centrally further up the stack.
Concrete user-visible improvements so far:
    - File paths in compiler/linker messages are clickable links now.
    - QtTest applications now create clickable links also when run
      as part of a build step, not just in the app output pane.

Task-number: QTCREATORBUG-22665
Change-Id: Ic9fb95b2d97f2520ab3ec653315e9219466ec08d
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

For symmetry with Utils::OutputFormatter.

Task-number: QTCREATORBUG-22665
Change-Id: I148fed69dba042ad3ef26e080829c31cd3f357fd
Reviewed-by: hjk <hjk@qt.io>

Use "flat" aggregation instead.
This is another step towards the formatter/parser merger.
Along the way, also fix some some subclasses (mostly in BareMetal) that
erroneously forwarded handled output to other parsers.

Task-number: QTCREATORBUG-22665
Change-Id: I12947349ca663d2e6bbfc99efd069d69e2b54969
Reviewed-by: hjk <hjk@qt.io>

Another step towards parser/formatter unification.

Task-number: QTCREATORBUG-22665
Change-Id: I6de86b3aee2c54585cdd4b06d21b0ea67300aeac
Reviewed-by: hjk <hjk@qt.io>

All parsers can now have search directories, not just the GnuMakeParser.
This allows us to get rid of the "task mangling", removing another
instance where the order of parsers in the chain mattered.

Task-number: QTCREATORBUG-22665
Change-Id: Id0d55522ae6800afd9f50ff36546224b0d8bb382
Reviewed-by: hjk <hjk@qt.io>

This makes IOutputParser structurally more similar to
Utils::OutputFormatter, which makes it simpler to explore possibilities
of somehow uniting these two related classes.

Task-number: QTCREATORBUG-22665
Change-Id: Ibb12ab6c8c785d863b9a921102a929864d0a5251
Reviewed-by: hjk <hjk@qt.io>

- Remove unneeded/unused functions.
- De-virtualize where possible.

In particular, after untangling a number of self-referential
redirections, it became apparent that the outputAdded()
infrastructure was entirely unused.

Change-Id: I51e1beed008df2727b42494b087efa476342397e
Reviewed-by: hjk <hjk@qt.io>

For some reason, Q_UNUSED includes already a semicolon, adding one
on the user side creates an additional empty statement.

Change-Id: I9c5e8fac381345a60792cb75e2938fd53958d3b0
Reviewed-by: Christian Stenger <christian.stenger@qt.io>