Specify folder to work on

[dettbarn]

Currently, all Igordoc scripts just work with the .ipf files present in the same folder, i.e. to generate a documentation you have to move the .ipf file to the Igordoc folder or vice versa.

It should be possible to specify a target folder on input, as an optional parameter to each of the bash scripts.

E.g.

$ ./make-markdown.sh path/to/folder/

should create a markdown documentation to all .ipf files located in path/to/folder/. This documentation should also be put into the same folder.