move foldsearch functions to autoload

--HG--
extra : amend_source : 4e62e4b01bd4ece7072b4de9ce2729b6b8311df1
extra : histedit_source : 27e59d6544e67ba7f8ec31c574def2368831ba8a%2C34e7fe253781716fa587b0c80eec5f25cd99e5a7
switch from buffer local to window local settings

--HG--
extra : histedit_source : a563c95fb64776c2e527dac2f8771786fb8dabd1
store only folds in view and other settings explicitly

--HG--
extra : amend_source : 3b3fd2102a41f00bb43ab326c3277e9671821327
extra : histedit_source : 9cf3d12991a95376161ffeb54aae8075bf850e69