Improve right prompt

[phra]

i made some small improvements to the right prompt of lambda theme and i would like to merge them to the main repository.

1. print green exit status if 0
2. print and format $CMD_DURATION

fixes #9

[phra]

@hasanozgan any update?

[js402882]

I have visually more subtle and much simpler implementation for $CMD_DURATION display (basically no more than 1 one-liner). If there would be response and interest from @hasanozgan I can prepare merge request for it.

[phra]

@js402882 i can give you access to my fork to update this PR if you want.

[phra]

@hasanozgan @js402882 is anyone alive guys?

[faogustavo]

@phra @hasanozgan I'm facing some problems with these changes.
After taking a look at the code I discovered that the problem is in the line 16.
The math done in this line, shows me an error message like this:

0.000001: value not completely converted

After commenting this line, everything works properly.

My setup is:

• OS: Linux (Debian 10 - but had the same problem on ubuntu 19.04 and 19.10)
• KDE IDE
• Using Hyper or Konsole

[alonsodomin]

Same happens in MacOS, there is a fix in #12.

To be honest, this should have never been merged, there is little value in the additional $CMD_DURATION info in the prompt and because of poor testing, it broke a perfectly working prompt.