First implementation, need answer https://github.com/nicolargo/glances/issues/1129#issuecomment-318489088

See e2912943.

- wrong continued indentation
- missing whitespace after ':'
- unused imports
- expected 2 blank lines after class or function definition

- Fix wrong import order
- Remove unused imports

We don't support Python 2.6 any longer.

As per [their blog post of the 27th April](https://blog.readthedocs.com/securing-subdomains/) ‘Securing subdomains’:

> Starting today, Read the Docs will start hosting projects from subdomains on the domain readthedocs.io, instead of on readthedocs.org. This change addresses some security concerns around site cookies while hosting user generated data on the same domain as our dashboard.

Test Plan: Manually visited all the links I’ve modified.

Add riemann to the index, otherwise it doesn't exist.

This patch introduces a new export method for sending metrics to
__Riemann__ server using _TCP_ protocol. The module can be enabled like
all the other exports in __Glances__, specifying the `--export-riemann`
option.

Sending metrics to Riemann requires
[bernhard](https://github.com/banjiewen/bernhard) that is
the most popular _Riemann client_ written in python.

In the configuration file you can only specify the `host` and `port`
that riemann is listening for new connections on. Later new options are
planned to be added like __SSL__ support and __UDP__.

Documentation and manpages are refreshed according to the modifications
in the config options and introducing the usage of Riemann export.
Signed-off-by: NGergő Nagy <grigori.grant@gmail.com>