[bugfix] fix compilation error on mac
[bugfix] fix the name of dynamic lib on mac
update common header
new classes
new class: Counter
make two connection classes implement from Counter
using public member function instead of private member when logging
add submodule http-parser
add HttpParser: a C++ wrapper of node.js' http-parser
new class: HttpMessage
update cmake config, add submodule http-parser
add new interface: Serializable
update HttpHeaders
new class HttpRequest
new class: HttpResponse
update class HttpMessage
change the implementation of HttpParser, make it a base class
add interface to HttpParser
update interface Connection
minor fix