Updated resetting pid only after completing non-debbugged process.

This changes the logic introduced by 78c44e60 as it interfered with
`done()` call from the debugger that prevented properly handling of
a process that stopped debugging, but continued execution.
Added `Detach process` command to stop debugging and continue process.
Updated lua interpreter to remove caching of executable path.

This allows updating `path.lua` from project config or changing
it without IDE restart.
Updated Mobdebug (0.555) to add support for `pause` debugger call.
Reordered markers to keep the curent line marker on top (#305).
Merge branch 'master' of https://github.com/pkulchenko/ZeroBraneStudio
remove obsolete tool