updated to 7.4.552

7.4.538  tests fail with small features plus Python
7.4.539  (after 7.4.530) crash when computing buffer count
7.4.540  (after 7.4.539) cannot build with tiny and small features
7.4.541  crash when doing a range assign
7.4.542  cannot specify the type of range for a user command
7.4.543  (after 7.4.232) "1,3s/\n//" joins two lines instead of three
7.4.544  warnings for unused arguments with a combination of features
7.4.545  highlighting for multi-line matches is not correct
7.4.546  repeated use of vim_snprintf() with a number
7.4.547  "vit" does not select multi-byte character at the end correctly
7.4.548  compilation fails with native version of MinGW-w64
7.4.549  function name not recognized correctly when inside a function
7.4.550  curs_rows() function is always called with second argument false
7.4.551  "ygn" may yank too much; Issue 295
7.4.552  langmap applies to Insert mode expression mappings