Correct file handler should be deleted

Previously, Jim_DeleteFileHandler() would indiscriminately
delete the first matching file handler in the list.
Instead, it should delete the file handler matching the event mask.

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Allow object pool to be disabled

Compile time option, for maintainer debugging

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Fix memory management of aio event handlers

It was possible for a handler to be deleted
(e.g. if the handler threw an error), but the
channel handle to still maintain a pointer to the
handler script.

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Minor code cleanups

Prefer Jim_String() and Jim_Length() over Jim_GetString() where it makes sense.
Use Jim_ListGetIndex() where success is guaranteed.

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Bump version to 0.75

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Update linenoise.c from github

For the following change:
    Fix a couple of compiler warnings

    With the colour prompt support.
    Also recognize '\e[m' as an escape sequence.
    Simplify countColorControlChars().

Signed-off-by: Steve Bennett <steveb@workware.net.au>
Merge branch 'master' of https://github.com/msteveb/jimtcl