Change some default option values

internal/config/settings.go

@@ -184,7 +184,7 @@ func GetGlobalOption(name string) interface{} {
 
 var defaultCommonSettings = map[string]interface{}{
 	"autoindent":     true,
-	"autosu":         true,
+	"autosu":         false,
 	"backup":         true,
 	"basename":       false,
 	"colorcolumn":    float64(0),
@@ -192,7 +192,7 @@ var defaultCommonSettings = map[string]interface{}{
 	"diffgutter":     false,
 	"encoding":       "utf-8",
 	"eofnewline":     false,
-	"fastdirty":      true,
+	"fastdirty":      false,
 	"fileformat":     "unix",
 	"filetype":       "unknown",
 	"ignorecase":     false,

runtime/help/options.md

@@ -95,10 +95,10 @@ Here are the available options:
    This is fast, but can be inaccurate. If `fastdirty` is off, then micro will
    hash the current buffer against a hash of the original file (created when
    the buffer was loaded). This is more accurate but obviously more resource
-   intensive. This option is only for people who really care about having
-   accurate modified status.
+   intensive. This option will be automatically disabled if the file size
+   exceeds 50KB.
 
-	default value: `true`
+	default value: `false`
 
 * `fileformat`: this determines what kind of line endings micro will use for
    the file. UNIX line endings are just `\n` (linefeed) whereas dos line