Make leaves and nodes tmp files paths platform independent

[StepanWorkV]

On windows graphviz throws cannot find file exceptions.
This is due to the hardcoded unix-style.

Example: C:\Users\username\AppData\Local\Temp/leaf191_25772.svg

[parrt]

@tlapusan looks ok to me. You?

[tlapusan]

Sorry for late response, just got back from vacation...

@parrt it look good for me also. Pulled the PR and double checked that it works also :). Curious how it worked until now on windows ?!

@StepanWorkV thanks for this PR. A very good improved to the library ! Hope that you enjoy using it 👍

[StepanWorkV]

Sorry for late response, just got back from vacation...

@parrt it look good for me also. Pulled the PR and double checked that it works also :). Curious how it worked until now on windows ?!

@StepanWorkV thanks for this PR. A very good improved to the library ! Hope that you enjoy using it 👍

Thanks!
It worked because on windows "/" can be in file name, thus when a file was generated it was stored as Temp/leaf191_25772.svg (just my guess, didn't verify that).

BTW please take a look at this issue, I have created that PR while trying to resolve it:
#298
(It didn't solve it though, I have provided some comments why, please let me know if you need some additional clarity)

[tlapusan]

@parrt I think we are good to merge this PR