Use SASS for CSS + static asset reoganization

Had been planning to use a more powerful preprocessor for CSS for a
while, so that I can also reorganize and clean up the CSS a bit. The
cleanup will come later, this is the first step to reorganize the build
system a bit and remove skingen.pl.

I moved all generated static assets to static/g/ (for _g_enerated),
including icons.png and js files. This simplifies management of
static/f/ and static/s/, which are fully in git.

Skins are now defined as sass files in css/skins/ with their images in
static/s/ using plain directory structure.

1 files changed, 1 insertions, 0 deletions

diff --git a/README.md b/README.md
index 8a645431..5225ac37 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,7 @@ Global requirements:
 - Elm 0.19.1
 - Graphviz
 - ImageMagick
+- sassc
 
 **Perl modules** (core modules are not listed):