data: indexer processes

* TaskBuildIndex starts seperate indexer processes and communicates via shared memory
* indexer processes get restarted if they fail
* indexer processes are killed when the app closes or crashes
* added utility class SharedMemory to allocate and access shared memory, providing basic data structures
* added SharedMemoryGarbageCollector for keeping track of running instances and cleaning up shared memory in case of a crash
* show errors for source files that crashed during indexing
* added basic exception handling to task scheduling
* added option to turn off processes and use threads in preferences, but still use shared memory

fortune cookie message = Good news from someone dear is coming soon.

src/lib_cxx/data/indexer/IndexerCommandCxx.cpp

@@ -20,6 +20,28 @@ IndexerCommandCxx::~IndexerCommandCxx()
 {
 }
 
+size_t IndexerCommandCxx::getByteSize() const
+{
+	size_t size = IndexerCommand::getByteSize();
+
+	for (auto i : m_systemHeaderSearchPaths)
+	{
+		size += i.str().size();
+	}
+
+	for (auto i : m_frameworkSearchPaths)
+	{
+		size += i.str().size();
+	}
+
+	for (auto i : m_compilerFlags)
+	{
+		size += i.size();
+	}
+
+	return size;
+}
+
 std::vector<FilePath> IndexerCommandCxx::getSystemHeaderSearchPaths() const
 {
 	return m_systemHeaderSearchPaths;