staff.py now uses method='full' to read data from card
Sector.write_block now behaves correctly with any sector method.
Added exception catch when executing library calls.
Multiple improvements in contract.py

+ initialization routines now use ByteArray syntax instead of direct ctypes manipulation.
+ fail block detection mechanism reworked to remove redundant code and dependencies:
  There is no more need for DYBNAMIC_A to know anything about sector it works with.
  Instead, callback parameter has been introduced to make caller handle actual block restore
  manually.
+ comments for DYNAMIC_A updated accordingly to the new functionality.
term.read_dynamic has been refactored according to changes in contract.DYNAMIC_A
Fixed GET api handlers
Extended sector information list with additional data.
Clarified comment on card_event
journey.init now uses ByteArray constructor.
Style fix
U2 Library update
Metaclass operation reordering
Removed unused parameter from journey.init and journey.remove signature
Implemented /api/term/init and /api/term/remove

+ u2py.term got init and remove functions similarly to journey
  * currently, only refillable contracts can be initialized
+ webapi.term got /api/term/init and /api/term/remove implemented using u2py.term
  * /api/term/init required |aidpix| parameter with contract identifier.
    This parameter is optional, with 0xD0130C being default value.
Version 1.6.2

Signed-off-by: stdk <std.feanor@gmail.com>