calc last modified time of files under a dir
[httpserver] read bind port from seafile.conf

* Sample conf

[httpserver]                    [httpserver]
port=8082                       port=8082
https=true                      https=false
privkey=/path/to/privkey
pemfile=/path/to/pem/file
also calc last modication time of dirs
remove unnecessary checks in configure.ac
[server] Allow setting history length for each repo.
[server] Allow selecting how many deleted files to show in recycle.
Avoid using python3 as default python interpreter.

Now if you want to build seafile in a system that has ptthon2/3,
you need to use the following command:
 1. ./configure PYTHON=/usr/bin/python2.7
 2. make
 3. make install
[gtk] Only use appindicator in Unity
fixed various compile problems
[http] Add file upload REST API.
[client] Fix transfer rate display.

* Display rate of the last second instead of this second.
* Display 0KB/s in repo.html.
[http] Fix block handle leak when downloading file.
[Mac] Normalize filenames before stroing it into index.

On Mac OS X with HFS+,
* file system APIs accept both NFC and NFD encoded paths;
* readdir() returns dname in NFD.

Internally, Seafile assumes all filenames are in UTF-8, NFC.

So after reading dname from filesystem, we should normalize
it to NFC.