[FIX] utf-8 encoding of resources PDF conversion

closes #1371
[MIN] i18n
[MIN] Removed unnecesary temp variable
[FIX] RoomBooking: Blockings bars

* closes #1289
* They span a whole day
* They are rendered in the furthermost layer
* They cannot be clicked
[FIX] RoomBooking: Reservation on blocked rooms

* Candidate bars: ajax click to check if user can override blocking
[MIN] PEP8