Improved working of BackupDialog

- improved layout
- automatically switch to output component when start is clicked
- coloured output for succes/error message
- highlighter for pg_dump output that highlights error lines

Note: all output of pg_dump goes to stderr because stdout is reserved for output of the backup data.

pglab/PgDumpOutputHighlighter.cpp

@@ -0,0 +1,19 @@
+#include "PgDumpOutputHighlighter.h"
+
+PgDumpOutputHighlighter::PgDumpOutputHighlighter(QTextDocument *parent)
+	: QSyntaxHighlighter(parent)
+{
+	m_errorFormat.setForeground(QColor(255, 128, 128));
+	m_errorFormat.setFontWeight(QFont::Bold);
+}
+
+PgDumpOutputHighlighter::~PgDumpOutputHighlighter()
+{
+
+}
+
+void PgDumpOutputHighlighter::highlightBlock(const QString &text)
+{
+	if (text.startsWith("pg_dump: error"))
+		setFormat(0, text.length(), m_errorFormat);
+}