Terminal: tab auto-complete doesn't correct folder casing

[alainbryden]

Steps to reproduce:

1. Have a folder created with upper-case letters, such as "Tasks/", and some scripts in this folder.
   

2. Type the folder name incorrectly as all-lower-case ("tasks/") then proceed to tab-autocomplete a file name.
   Note that the auto-complete will correct the case of the filename if you typed any letters in the incorrect case, but it will not correct the case of the folder name:
   

3. This will now open a new file (in a new folder) rather than the existing file you tab-auto-completed:
   

Acceptable solutions (IMO):

• Correct the casing in the full path (including folder name) when we tab-autocomplete - currently we just correc the filename casing.
  or
• Once the folder name has been completed ("/" is present in the path) - tab auto-complete should no longer list any files, because the folder does not exist. Specifically, it should not list files that exist in a similarily-named folder, but with different casing.

A side-effect of the current behaviour (ignoring folder casing when auto-completing) is that if the user creates two folders with the same name but different casing, these folders are merged in the auto-complete box. In this case, since each folder now has a file named "backdoor-all-servers.js", this entry appears twice:

[gmcew]

For reference for any potential PR on this; there's a few other autocomplete problems at #522 and #1473 which may be worth considering. As far as I can see this is the first issue referencing automplete's case-sensitivity, though I might have missed a previous mention.