- fix hof when user is deleted - user/:id/stat only show available problem for non-admin user

add missing file

remove whitelist attribute from default config

update master

fix various bug (grafted from cb6577a84dff16a5d7ba91166873cc8a2e2a2628)

- add compiler comment - fix error when problem is not present (grafted from 5dcd02c21a697ca0a770d0aab8380eacc42eba04)

- start adding testcases into database - fix download button for score report (grafted from aabe2eab4ee28760618043fc980bb5d5aaca5311)

- clean up link to problem stat and user stat (grafted from 45d1e12e9794a23a5431222fe2f4c7461d73a529)

fix destroy for user and problem (grafted from 56e542ecc72e8d85b776f34c64fe90d3ea4ae9e9)

fix destroy button link (grafted from b75d9cfe4ee0550d574de4c4836ecc36c9354c53)