Multi-module builds with common bib file

**Given**:
- multi-module build with multiple LaTeX projects
- multiple projects use same bib file located in root (referenced with relative path in `build.gradle`s

**When**:
- call `gradle pdfLatex -i -t` to react to changes

**Expected**:
- when any tex file changes, the appropriate project is rebuilt

**Actual**:
- only one (apparently random) project gets built