lib/cppparser/lexer.{h,cpp} cosmetics and error detection improvement:

- Move function bodies from header file to implementation file.
  - Token::Token(const QString & text)
  - Token::Token(int type, int position, int length, const QString& txt)
  - Token::Token(const Token& source)
  - Token& Token::operator = (const Token& source)
  - Token::operator int () const
  - bool Token::operator == (const Token& token) const
  - bool Token::isNull() const
  - int Token::type() const
  - void Token::setType(int type)
  - int Token::position() const
  - QString Token::text() const
  - void Token::setStartPosition(int line, int column)
  - void Token::setEndPosition(int line, int column)
  - void Token::getStartPosition(int* line, int* column) const
  - void Token::getEndPosition(int* line, int* column) const
  - void Token::setPosition(int position)
  - unsigned int Token::length() const
  - void Token::setLength(unsigned int length)
  - const CHARTYPE* Lexer::offset(int offset) const
  - int Lexer::getOffset(const QChar* p) const
  - Lexer::readWhiteSpaces(bool skipNewLine, bool skipOnlyOnce)
  - bool Lexer::recordComments() const
  - void Lexer::setRecordComments(bool record)
  - bool Lexer::recordWhiteSpaces() const
  - void Lexer::setRecordWhiteSpaces(bool record)
  - QString Lexer::source() const
  - int Lexer::index() const
  - void Lexer::setIndex(int index)
  - const Token& Lexer::nextToken()
  - const Token& Lexer::tokenAt(int n) const
  - const Token& Lexer::lookAhead(int n) const
  - int Lexer::tokenPosition(const Token& token) const
  - void Lexer::nextChar()
  - void Lexer::nextChar(int n)
  - void Lexer::readIdentifier()
  - bool isTodo(const QString& txt, int position); static in cpp file
  - bool isFixme(const QString& txt, int position); static in cpp file
  - void Lexer::readLineComment()
  - void Lexer::readMultiLineComment()
  - void Lexer::readCharLiteral()
  - void Lexer::readStringLiteral()
  - void Lexer::readNumberLiteral()
  - int Lexer::findOperator3() const
  - int Lexer::findOperator2() const
  - bool Lexer::skipWordsEnabled() const
  - void Lexer::setSkipWordsEnabled(bool enabled)
  - bool Lexer::preprocessorEnabled() const
  - void Lexer::setPreprocessorEnabled(bool enabled)
  - int Lexer::currentPosition() const
  - const QChar Lexer::currentChar() const
  - QChar Lexer::peekChar(int n) const
  - bool Lexer::eof() const
  - bool Lexer::reportWarnings() const
  - void Lexer::setReportWarnings(bool enable)
  - bool Lexer::reportMessages() const
  - void Lexer::setReportMessages(bool enable)
  - void Lexer::insertCurrent(const QString& str)
- At Lexer function
    readWhiteSpaces(bool skipNewLine=true, bool skipOnlyOnce=false)
  change return type from void to bool, return false on EOF.

lib/cppparser/lexer.cpp
- In Lexer::nextChar functions return immediately if m_ptr is beyond
  m_endPtr.
- In Lexer::readLineComment() break out of while-loop if
  currentPosition() returns error.
- In Lexer::readMultiLineComment() break out of while-loop if
  currentPosition() returns error.
- In Lexer::readCharLiteral() while-loop add safety check that
  currentPosition() returns valid position.
- In Lexer::readStringLiteral() while-loop add safety check that
  currentPosition() returns valid position.
- In Lexer functions findOperator3, findOperator2, insertCurrent add
  initial check that currentPosition() returns valid position.
- In Lexer function getOffset return -1 for error (argument `p' out of
  range of `src').
- In Lexer function nextToken,
  - return immediately if readWhiteSpaces() returns error;
  - return immediately if currentPosition() returns error.
- In Lexer::tokenize() replace "for (;;)" loop by
  "while (currentPosition() >= 0)".
- In Lexer::readArgument() return empty string if readWhiteSpaces()
  returns error.
- In Lexer functions macroDefined, processDefine, processInclude,
  macroPrimary,
  - return 0 if readWhiteSpaces() returns error;
  - return 0 if currentPosition() returns error.
- In Lexer::macroMultiplyDivide() replace "for (;;)" loop by
  "while (readWhiteSpaces(false))".
- In Lexer functions macroAddSubtract, macroRelational, macroEquality,
  macroBoolAnd, macroBoolXor, macroBoolOr, macroLogicalAnd,
  macroLogicalOr return result immediately if readWhiteSpaces() returns
  error.
- In Lexer::macroExpression() return 0 if readWhiteSpaces() returns
  error.