am-dbg: UI becomes less responsive after a longer heavy streaming

[pancsta]

am-dbg becomes less responsive after a longer heavy streaming. It could be either UI or data parsing leak.

Steps:

• start the pubsub simulator for 10min with 20 peers and 30 topics (defaults)
• keep it in the tail mode until it finishes
• go back / forth

Result:

• noticeable delay

Workarounds:

• export & --import-data
• switch to another machine and back

[pancsta]

LogView seems to be the issue, could use caching or simply a periodic restart (eg every 1000 cursor moves).

[pancsta]

Additionally there seem to be a leak in tcell (*CellBuffer) Resize, as visible on this dump after 10min of streaming.

Repro: focus switching is very slow

[pancsta]

Disabling word wrap fixes most of the issues.

TODO:

• fix the resize leak (no resizing takes place at all)
• cook up a custom dynamic rendering for the log view
  • also needed for #102

Steps:

• load the sim dump
• hold Tab to rotate focus

Result: focus change is slow for sim, but fast for eg sim-p0