Add icons option to Disk Space block

[jamesmcm]

Adds icons option to use hard disk icon instead of alias in the DiskSpace block.

Tested with FontAwesome4 (but I looked up glyph values for the others, to find comparable icons).

This is my first PR, please let me know if there is anything else to check!

[ammgws]

Maybe we could add a format string instead and have qualifiers {icon}, {alias}, {path}, {available} etc.

[jamesmcm]

Sure, is there another block which has an example of this?

[ammgws]

Search blocks.md for "format", there are a few that could be used as a reference.

[ammgws]

Let me know if you need some help

[jamesmcm]

@ammgws done 🙂

Example:

I also made some changes to the way the alert state is triggered too, to allow for triggering on an absolute amount used, etc.

[jamesmcm]

@ammgws the only thing I dislike is that the 2 decimal places is hardcoded in, rather than being part of FormatTemplate, at the moment I see it only pushes the pre-formatted values matching keys:

i3status-rust/src/util.rs

Line 434 in 735fc75

"{}",

But maybe that could be extended to allow for stuff like {free:.0} etc. in the config.

[GladOSkar]

I was also wondering if decimal control could be integrated into the format string.

When thinking about things like the net or the speedtest block, it would be neat to be able to define the precision separately for the different displayed values. Ideally the syntax would allow to define all 3 arguments of the format_speed() function added in #704 / #707, like for example

Free: {free:3:G:B} for Free: 21.9GB

or

Uplink: {up:2:M:b}/s for Uplink: 50Mb/s

[jamesmcm]

@ammgws the above issues are fixed 🙂

[ammgws]

What's going on with that diff for blocks.md?

[jamesmcm]

Oops, looks like it changed it to UNIX line endings, I can switch it back tonight, or we could just swap it to that like the rest of the files are.

[jamesmcm]

@ammgws so to confirm shall I switch it back to DOS line endings, or shall we just convert it to UNIX line endings like the rest of the files?

[ammgws]

Actually could you change it back for now? After this is merged submit another PR to fix the line endings.

[jamesmcm]

@ammgws done :)

[ammgws]

Thanks!