Test: added more tests to htmlFileHandler.
Enh: Don't assign pagelet options to real pagelets. Instead pass them as function argument.
New: added a "navigation" pagelet to display site navigation menus.
Enh: added navigation menu to be displayed on the front page.
Test: added a navigation pagelet test.
Test: added more tests to htmlFileHandler to check 304 HTTP response.
Enh: load RequireJs from the same static domain instead of cdnjs.cloudflare.com.

No need to resolve one more DNS. Can combine RequireJS configurations
inside the same file.
Enh: redirect root domain requests to www subdomain.
v0.1.9: redirect root domain requests to www subdomain.