Improvement of L1Vector, 2 bug fixes

/// L1Vector class is a wrapper around std::vector.
/// It does the following:
/// 1. resizes the vector without initializing the new elements
/// 2. controls the out-of-range access in debug mode
/// 3. warns when the preallocated capacity is not big enough
/// 4. blocks usage of boolean vectors, as they have a special
///    space-optimized but slow implementation in std. (Use L1Vector<char> instead).