use accessor instead of direct access to field. refs #407.

accessing field directly makes debug little hard, because
IDE cannot make 'call hierarchy' correctly. and it is good
habit on OOP programming, I think.
return currentURL instead of redirectURL. refs #407.

we can use curent URL to redirect in normal case, so
just use 'currentURL' instead of 'redirectURL' if
redirectURL is not specified.
switch to jackson from json-lib. see #316.
unify exception handling
merge public/js to public/javascripts
removed unused css
moved spinner.gif into public/images
move resource for bootstrap into public/images
Merge pull request #424 from eller86/unify-directory

Unify directory
Merge pull request #422 from eller86/316-remove-json-lib

switch to jackson from json-lib
removed unused extension. refs #428

we do not have to add extension to URI.
just remove it would solve our problem.
removed needless extension. refs #430
Merge pull request #431 from eller86/fix-430

removed needless extension. refs #430
Merge pull request #429 from eller86/fix-428

removed unused extension. refs #428
Merge pull request #425 from eller86/407-redirect-from-anywhere

redirect after sign in from anywhere