Merge pull request #710 from haiwen/fix-win-strftime

fixed strftime on win32 server, Closes haiwen/seafile-client#134
[server] rename httpserver to fileserver

The name "httpserver" is misleading, since it only handles raw file
upload/download.
Merge pull request #715 from haiwen/fserver

[server] rename httpserver to fileserver
[build] Add CMake Build System

  - Reflect the httpserver->fileserver changes
  - Set SOVERSION of libseafile to 0 as the same as what autoconf scripts do