Add check to skip parsing of break lines in castep band structure k point paths.

[azanre]

Closes #200 .

[ajjackson]

Thanks for this. I'm struggling to find documentation of this feature; it is mentioned in this old docs archive:

https://www.tcm.phy.cam.ac.uk/castep/documentation/WebHelp/content/modules/castep/keywords/k_bs_kpoint_path_castep.htm

but not in the current docs https://www.tcm.phy.cam.ac.uk/castep/documentation/WebHelp/content/modules/castep/keywords/k_bs_kpoint_path_castep.htm

or in the built-in castep -h bs_kpoint_path. So there is little surprise it was overlooked!

Do you have a small sample file that could be used to check this is working as expected, and included in the test suite?

[azanre]

It's also mentioned in the castep-docs repo, but definitely not easy to find! https://github.com/castep-docs/castep-docs/blob/develop/docs/documentation/Input_Files/cell_file.md
I'll add an example .cell file and write a unit test for it as well

[azanre]

Unit test added - let me know if any more changes are needed

[ajjackson]

Looks good to me