Lots of updates:

1. Scrolling and click to set the cursor works.
2. GUI now uses Brass Mono as the font.
3. A lot of stability and other updates.

Editor.cc

@@ -0,0 +1,121 @@
+#include "Editor.h"
+
+#include <algorithm>
+#include <utility>
+
+
+Editor::Editor() = default;
+
+
+void
+Editor::SetDimensions(std::size_t rows, std::size_t cols)
+{
+	rows_ = rows;
+	cols_ = cols;
+}
+
+
+void
+Editor::SetStatus(const std::string &message)
+{
+	msg_   = message;
+	msgtm_ = std::time(nullptr);
+}
+
+
+Buffer *
+Editor::CurrentBuffer()
+{
+	if (buffers_.empty() || curbuf_ >= buffers_.size()) {
+		return nullptr;
+	}
+	return &buffers_[curbuf_];
+}
+
+
+const Buffer *
+Editor::CurrentBuffer() const
+{
+	if (buffers_.empty() || curbuf_ >= buffers_.size()) {
+		return nullptr;
+	}
+	return &buffers_[curbuf_];
+}
+
+
+std::size_t
+Editor::AddBuffer(const Buffer &buf)
+{
+	buffers_.push_back(buf);
+	if (buffers_.size() == 1) {
+		curbuf_ = 0;
+	}
+	return buffers_.size() - 1;
+}
+
+
+std::size_t
+Editor::AddBuffer(Buffer &&buf)
+{
+	buffers_.push_back(std::move(buf));
+	if (buffers_.size() == 1) {
+		curbuf_ = 0;
+	}
+	return buffers_.size() - 1;
+}
+
+
+bool
+Editor::OpenFile(const std::string &path, std::string &err)
+{
+	Buffer b;
+	if (!b.OpenFromFile(path, err)) {
+		return false;
+	}
+	AddBuffer(std::move(b));
+	return true;
+}
+
+
+bool
+Editor::SwitchTo(std::size_t index)
+{
+	if (index >= buffers_.size()) {
+		return false;
+	}
+	curbuf_ = index;
+	return true;
+}
+
+
+bool
+Editor::CloseBuffer(std::size_t index)
+{
+	if (index >= buffers_.size()) {
+		return false;
+	}
+	buffers_.erase(buffers_.begin() + static_cast<std::ptrdiff_t>(index));
+	if (buffers_.empty()) {
+		curbuf_ = 0;
+	} else if (curbuf_ >= buffers_.size()) {
+		curbuf_ = buffers_.size() - 1;
+	}
+	return true;
+}
+
+
+void
+Editor::Reset()
+{
+	rows_    = cols_ = 0;
+	mode_    = 0;
+	kill_    = 0;
+	no_kill_ = 0;
+	dirtyex_ = 0;
+	msg_.clear();
+	msgtm_  = 0;
+	uarg_   = 0;
+	ucount_ = 0;
+	buffers_.clear();
+	curbuf_ = 0;
+}