update links to optional

Former-commit-id: db9e17725769505b061c77033f29aeb267df0eb7

README.md

@@ -19,7 +19,7 @@ header file contains a single function (e.g. `igl/cotmatrix.h` contains
 stored in an n-by-3 matrix of vertex positions V and an m-by-3 matrix of
 triangle indices F. 
 
-_Optionally_ the library may also be [pre-compiled](build/) into a statically
+_Optionally_ the library may also be [pre-compiled](optional/) into a statically
 linked library, for faster compile times with your projects. This only effects
 compile time (run-time performance and behavior is identical). If in doubt, use
 the header-only default mode: (i.e. just include the headers you want to use).

scripts/update_gh-pages.sh

@@ -32,8 +32,8 @@ echo "$HEADER" \
   git commit -m "update google-soc/index.html to match google-soc/google-soc.md" google-soc/google-soc.md google-soc/index.html 
 
 echo "$HEADER" \
-  | cat - build/README.md | multimarkdown -o build/index.html && \
-  git commit -m "update index.html to match README.md" build/README.md \
-  build/index.html
+  | cat - optional/README.md | multimarkdown -o optional/index.html && \
+  git commit -m "update index.html to match README.md" optional/README.md \
+  optional/index.html
 
 git push origin gh-pages && git checkout master && git merge gh-pages && git push

tutorial/tutorial.md.REMOVED.git-id

@@ -1 +1 @@
-950c99bc449b8e5de9f3f0619c1f33ce04232900
+c2c64bc4dca6502cf13e254fa512d9f9feca182f