Fix some sequences not printing in titles/filenames

[lefth]

This fixes issue #51: for example "temp\home" is shown as "temp ome".

[dyphire]

I think the better change is:

p = p:gsub("\\", "/")
     :gsub("{", "\\{")
     :gsub("^ ", "\\h")

This will unify the display of path format. And this change also should be applied to the other two scripts: SimpleBookmark.lua, SmartCopyPaste_II.lua.

[lefth]

Done.

Though I don't like changing the path separator, the code is short this way, and that's ideal because writing lua modules or shared functions for recent versions of mpv is tricky.

[Eisa01]

I believe I have written a function that deals with escape sequences, because there is multiple escape_sequences not dealt with in this PR. I must have forgot to call the existing method on this list.

[Eisa01]

I will keep this open for reference until changes are made to fix issue #51

[Eisa01]

Only remaining is to migrate the changes of 2044e4397320943f38960d1b99cf4d0c59808a4b to SimpleHistory, and SmartCopyPaste