Console: Add support for read-only 'Variable' commands

Console: Implement custom argument parser support
Utils: Add Boost.Parameter has_parameter helper
senfscons: Show reason (error message) in the CompileCheck builder

Console: Documentation

Utils: Add some more type_traits
Console: Implement parsed command attributor

Console: Fix parsing of commands in the presence of default arguments
Console: Generate automatic online help for automatically parsed commands

Console: First implementation of command argument parsing
doclib: Better doxygen header/footer dependency handling
add missing Console includes