Fix some path normalization on windows

lib/page/index.js

@@ -30,7 +30,7 @@ function Page(book, filename) {
     this.description = '';
 
     // Relative path to the page
-    this.path = filename;
+    this.path = location.normalize(filename);
 
     // Absolute path to the page
     this.rawPath = this.book.resolve(filename);

lib/utils/location.js

@@ -34,9 +34,12 @@ function normalize(s) {
 // dir: directory parent of the file currently in rendering process
 // outdir: directory parent from the html output
 function toAbsolute(_href, dir, outdir) {
-    outdir = outdir == undefined? dir : outdir;
-
     if (isExternal(_href)) return _href;
+    outdir = outdir == undefined? dir : outdir;
+    
+    _href = normalize(_href);
+    dir = normalize(dir);
+    outdir = normalize(outdir);
 
     // Path "_href" inside the base folder
     var hrefInRoot = path.normalize(path.join(dir, _href));