Add unit tests.

These test the complete workflow as the user experiences it when
clicking "Start".
Intended usage:
    (1) Run sdktool to set up a kit with the toolchain you want
        to test against (using a temporary directory).
        The tests assume exactly one Kit to be present.
    (2) Start Creator with a matching settings path and
        "-load ClangStaticAnalyzer -test ClangStaticAnalyzer".
    (3) Repeat until all toolchains have been tested.
The initial implementation tests one trivial source file
with both qbs and qmake.

Change-Id: I810f23e2990a789a4dd9f1dd16335fbcf5c5f39f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

plugins/clangstaticanalyzer/clangstaticanalyzertool.cpp

@@ -54,6 +54,7 @@ ClangStaticAnalyzerTool::ClangStaticAnalyzerTool(QObject *parent)
     , m_diagnosticView(0)
     , m_goBack(0)
     , m_goNext(0)
+    , m_running(false)
 {
     setObjectName(QLatin1String("ClangStaticAnalyzerTool"));
     setRunMode(ProjectExplorer::ClangStaticAnalyzerMode);
@@ -206,6 +207,7 @@ void ClangStaticAnalyzerTool::startTool(StartMode mode)
     QTC_ASSERT(project, return);
     m_projectInfoBeforeBuild = CppTools::CppModelManager::instance()->projectInfo(project);
     QTC_ASSERT(m_projectInfoBeforeBuild.isValid(), return);
+    m_running = true;
     ProjectExplorerPlugin::instance()->runProject(project, runMode());
 }
 
@@ -220,6 +222,11 @@ void ClangStaticAnalyzerTool::resetCursorAndProjectInfoBeforeBuild()
     m_projectInfoBeforeBuild = CppTools::ProjectInfo();
 }
 
+QList<Diagnostic> ClangStaticAnalyzerTool::diagnostics() const
+{
+    return m_diagnosticModel->diagnostics();
+}
+
 void ClangStaticAnalyzerTool::onEngineIsStarting()
 {
     QTC_ASSERT(m_diagnosticModel, return);
@@ -246,6 +253,8 @@ void ClangStaticAnalyzerTool::onEngineFinished()
     AnalyzerManager::showStatusMessage(issuesFound > 0
       ? AnalyzerManager::tr("Clang Static Analyzer finished, %n issues were found.", 0, issuesFound)
       : AnalyzerManager::tr("Clang Static Analyzer finished, no issues were found."));
+    m_running = false;
+    emit finished();
 }
 
 void ClangStaticAnalyzerTool::setBusyCursor(bool busy)