Windows: path normalization and corner cases for TeX path escaping

[jonasmalacofilho]

• [x] normalize \include paths
• [x] normalize all other paths
• [x] normalize generated paths on html and TeX
• test and validate TeX path escaping on Windows and Linux

[jonasmalacofilho]

Difficulties with TeX path escaping:

• windows backslashes must be translated to forward slashes: C:/a/b.jpg
• dots in the path require that the base path be protected by {}: {a/b.c/d}.jpg
• spaces in paths: it's a mess
• other chars: it gets worse
• absolute paths in general: might fail on some tex drivers

So, the best path:

• [x] use an asset store (similar to what we use for html generation)
• [x] only output relative paths for TeX