add ignorecase option for case insensitive search

Mentioned in #69.

comp.go

@@ -59,6 +59,9 @@ var (
 		"hidden",
 		"nohidden",
 		"hidden!",
+		"ignorecase",
+		"noignorecase",
+		"ignorecase!",
 		"preview",
 		"nopreview",
 		"preview!",

doc.go

@@ -72,6 +72,7 @@ The following options can be used to customize the behavior of lf:
     dirfirst    boolean  (default on)
     globsearch  boolean  (default off)
     hidden      boolean  (default off)
+    ignorecase  boolean  (default off)
     preview     boolean  (default on)
     reverse     boolean  (default off)
     wrapscan    boolean  (default on)

docstring.go

@@ -76,6 +76,7 @@ The following options can be used to customize the behavior of lf:
     dirfirst    boolean  (default on)
     globsearch  boolean  (default off)
     hidden      boolean  (default off)
+    ignorecase  boolean  (default off)
     preview     boolean  (default on)
     reverse     boolean  (default off)
     wrapscan    boolean  (default on)

eval.go

@@ -41,6 +41,12 @@ func (e *setExpr) eval(app *app, args []string) {
 	case "hidden!":
 		gOpts.hidden = !gOpts.hidden
 		app.nav.renew(app.nav.height)
+	case "ignorecase":
+		gOpts.ignorecase = true
+	case "noignorecase":
+		gOpts.ignorecase = false
+	case "ignorecase!":
+		gOpts.ignorecase = !gOpts.ignorecase
 	case "preview":
 		gOpts.preview = true
 	case "nopreview":

nav.go

@@ -369,6 +369,9 @@ func (nav *nav) cd(wd string) error {
 }
 
 func match(pattern, name string) (matched bool, err error) {
+	if gOpts.ignorecase {
+		pattern, name = strings.ToLower(pattern), strings.ToLower(name)
+	}
 	if gOpts.globsearch {
 		return filepath.Match(pattern, name)
 	} else {

opts.go

@@ -7,6 +7,7 @@ var gOpts struct {
 	dirfirst   bool
 	globsearch bool
 	hidden     bool
+	ignorecase bool
 	preview    bool
 	reverse    bool
 	wrapscan   bool
@@ -30,6 +31,7 @@ func init() {
 	gOpts.dirfirst = true
 	gOpts.globsearch = false
 	gOpts.hidden = false
+	gOpts.ignorecase = false
 	gOpts.preview = true
 	gOpts.reverse = false
 	gOpts.wrapscan = true