Closes #102

Still use GOGS_WORK_DIR and GOGS_CUSTOM env variables
as a fallback if the equivalent GITEA_* are not set,
warning user about the need for change.

Does not change "gogs" to "gitea" in webhook type name
Because "gogs" hook type is part of the API (routes) and used
in templates...

Closes #87

If the init script is called with `status`, the rc.subr(8) routines check if
the first argument associated with the pid in the pidfile is equal to
`procname`. By default, `procname` is equal to the value of `command`. In our
case, `command` contains a space (i.e. has multiple arguments), so `procname`
can never be equal to the first argument of the command associated with the
pid.

Set `procname` to the first argument of `command` to fix the `status` command
of the init script.

- use start-stop-daemon's chuid feature insted of su
  - using `su -c` breaks if the git user has no usable shell
  - this fixes #1025
- put --test before --exec, instead it gets passed to gogs
- set cwd via --chdir

We should be *sourcing* `/etc/sysconfig/gogs`, not *executing* it, don't we?

Implies 2 running child, so the `stop` command usually needs a `KILL` instead of a `TERM` to close properly so I reduced it to 1 second to get quickly with the `KILL` signal.

Compatible with "/etc/default/gogs" configuration file for adding or overwriting values.
Based on "/etc/init.d/skeleton" and tested on Raspbian 2014-06-20 (Debian 7.5 [Wheezy] ARM)

[TO FIX] For some reason, it's necessary to remove the value of RUN_USER from the app.ini configuration file because the following error occurs:
2014/09/28 18:12:53 [setting.go:182 NewConfigContext()] [E] Expect user(git) but current user is: