added explicit to constructors to prevent implicit type conversions

for example, this will prevent "Token token = 47" because this is an
undesired implicit conversion from an integer, which would have been
allowed without the 'explicit' keyword on the constructor definition
for "Token(int column = -1)"

commandline.h

@@ -45,7 +45,7 @@ class CommandLine
 	QTextStream m_cout;
 	QString m_usage;
 public:
-    CommandLine(const QStringList &args);
+    explicit CommandLine(const QStringList &args);
 	~CommandLine();
 
 	bool processed(void) const  // if processed then exit program

parser.h

@@ -54,7 +54,7 @@ class Parser
 	void skipWhitespace();
 	int scanWord(int pos, DataType &datatype, bool &paren);
 public:
-	Parser(Table &table): m_table(table) {}
+	explicit Parser(Table &table): m_table(table) {}
 	void setInput(const QString &input)
 	{
 		m_input = input;

test_ibcp.h

@@ -64,7 +64,7 @@ class Tester
 	QString m_testFileName;		// name of test file (OptFile only)
 	QString m_errorMessage;		// message if error occurred
 public:
-	Tester(const QStringList &args);
+	explicit Tester(const QStringList &args);
 	~Tester(void) {}
 
 	static QStringList options(void);

token.h

@@ -67,7 +67,7 @@ class Token
 	};
 
 public:
-	Token(int column = -1)
+	explicit Token(int column = -1)
 	{
 		m_column = column;
 		m_length = 1;

translator.h

@@ -176,7 +176,7 @@ class Translator
 	QString m_errorMessage;			// message of error that occurred
 
 public:
-	Translator(Table &table): m_table(table), m_output(NULL),
+	explicit Translator(Table &table): m_table(table), m_output(NULL),
 	    m_pendingParen(NULL), m_errorToken(NULL) {}
 	~Translator(void)
 	{