clean up for coding style
Brand new filesystem framework
Introduce new file operation framework
make them right
typedef type_index and remove including of unneeded headers
planet::close(): unregister operations after releasing
planetfs_main: add exception handling to main
delete utils
Add supports for dns service, tcp client and packet socket
Add examples for each operation
Remove unneeded white spaces
core_file_system: ctor now requires mode of root
Add README
Implement utimens functionality
dns_op: fix memory leak when an exception occurred
Add support for tcp server functionality
Merge branch 'mod_fs'

 Rewrite the internal filesystem framework
and port file operations to the new framework
 On the new framework, all operations must inherit
planet_operations and implement the static function
named `is_matching_path`
 To install new operations just call
core_file_system::install_op<new_op>()