This adds new functions to get plugins path info, find out if a directory
exists, make a new one, remove one, etc. It also creates a file environment
for user-supplied Lua scripts, to prevent global variable contamination as
well as supply the script-specific file name. Some other minor cleanup was
done as I found them.
A new testsuite was added to test the existing and new directory functions.
Change-Id: I19bd587b5e8a73d89b8521af73670e023314fb33
Reviewed-on: https://code.wireshark.org/review/832
Reviewed-by: Anders Broman <a.broman58@gmail.com>
Evan Huus