version 3.6.1

Fixed

• workaround error in SFINAE with MSVC
• compilation error in <filesystem> with MinGW (@chronoxor) (#136)
• fix comment duplication while serialization (#131)
• fix comment disappearance while serialization
• fix empty array serialization (#142)
• avoid string::back on an empty string (#141)
• add missing include files (@amerry) (#144)
• fix typo in an error message (@sneakypete81) (#148)
• added TOML11_DISABLE_STD_FILESYSTEM to disable <filesystem> manually (related to: #150)