Since otherwise we can't forward declare it.

Reviewed-by: thorbjorn

 * Rework IBuildParser:
    * Remove name() method.
    * Remove enterDirectory and leaveDirectory signals.
    * Allow chaining of parsers.
 * Rename IBuildParser to IOutputParser.
 * Implement GnuMakeParser.
    * Remove entering/leaving directory related code from all other parsers
    * Move filename fixup heuristic based on entering/leaving directory
      massages from gnumake here from AbstractMakeStep.
 * Add outputParser method to ToolChain: This removes the need to map
   toolchains to BuildParser names in the BuildSteps.
 * Enhance AbstractProcessStep to accept a IOutputParser to parse its output.
 * Remove AbstractMakeStep.
 * Set the appropriate Parsers in all classes deriving from AbstractProcessStep
   and append the ToolChain's parser to the parser chain.
 * Remove BuildParserFactories: There is no more need for them.
 * Remove constants used to identify the BuildParsers.
 * Clean up some names:
    * Replace stdOut with stdOutput.
    * Replace addToTaskWindow with addTask and addToOutputWindow with
      addOutput. Do this wherever it is not yet clear that this will end up
      in the Task/Output window.

Reviewed-by: dt

 * Use Task class in addToTaskWindow(...) signal. This introduces
   support for task categories into the BuildParsers.
 * Add a task category for buildsystem issues.
 * Update existing BuildParsers to new API and assign their
   tasks to the Compile or Buildsystem task category.

Reviewed-By: dt

Rename BuildParserInterface to IBuildParser to comply with
latest naming conventions.

Reviewed-By: con

 * Incorporate new TaskWindow changes.

Reviewed-By: kkoehne

 * Handle Warnings by the perl build scripts run by ABLD.
 * Handle critical failures in CPP on windows.

Reviewed-By: con

This is a initial version including
 * ABLD error parsing
 * RVCT compiler output parsing.

Reviewed-By: con