Compilation working directory could default to gummi working directory

[christophra]

Steps to reproduce:

1. Directory contains ./my.cls
2. Open gummi ./sub/doc.tex which uses \documentclass{my}
3. Compile won't work since it looks for the class file in ./sub/.

Expected behaviour:
Document compiles. Of course my expectation is subjective, but that's e.g. how rubber ./sub/doc.tex would work.

I tried to work around this using Gummi's "project" feature:

1. Open a file in the root directory
2. Create a project
3. Add ./sub/doc.tex
4. As expected, the "Project path" is the directory containing my.cls
   But nevertheless, compiling the document does not find the class file.

I would really love to use Gummi as a tool to pull up a TeX file and quickly see the effect of minor changes. These could be files which normally receive major edits elsewhere; so ideally, setting up projects etc. wouldn't be needed, when gummi already has the necessary information from its own working directory.