rename _{task,type}_strings to {TASK,TYPE}_STRINGS

should be treated as public constants
removed duplicate
added remote_agent QA
bugfixing
execution up to the point of initialization
WIP
fixed sinks handling
execution seems to work
moved to a simpler UI approach

This model based view thing with dropdown menus just didn't work out,
and I spent faaar too much time on it
changed table head spacings
added qa before I forget
saved json to temporary file instead of cStringIO\n\n closer to reality
fixed file delegate
update
worked on UI; big squash
ui beautification
beautification
__init__ fixes (cherry-pick to master)
Michael Dicken's not-double-shebang-fix
added task_frontend executable