add hyperlink and formula cell support

cell_range.go

@@ -0,0 +1,59 @@
+package xls
+
+import (
+	"fmt"
+)
+
+type Ranger interface {
+	FirstRow() uint16
+	LastRow() uint16
+}
+
+type CellRange struct {
+	FirstRowB uint16
+	LastRowB  uint16
+	FristColB uint16
+	LastColB  uint16
+}
+
+func (c *CellRange) FirstRow() uint16 {
+	return c.FirstRowB
+}
+
+func (c *CellRange) LastRow() uint16 {
+	return c.LastRowB
+}
+
+func (c *CellRange) FirstCol() uint16 {
+	return c.FristColB
+}
+
+func (c *CellRange) LastCol() uint16 {
+	return c.LastColB
+}
+
+type HyperLink struct {
+	CellRange
+	Description string
+	TextMark    string
+	TargetFrame string
+	Url         string
+}
+
+func (h *HyperLink) String(wb *WorkBook) []string {
+	res := make([]string, h.LastColB-h.FristColB+1)
+	str := fmt.Sprintf("%s(%s)", h.Description, h.Url)
+	for i := uint16(0); i < h.LastColB-h.FristColB+1; i++ {
+		res[i] = str
+	}
+	return res
+}
+
+// func (h *HyperLinkCR) ParseFrom(buf io.ReadSeeker) {
+// 	if h.Flags&0x1 != 0 {
+// 		binary.Read(buf, binary.LittleEndian, &richtext_num)
+// 	}
+// 	if h.Flags&0x4 != 0 {
+// 		binary.Read(buf, binary.LittleEndian, &phonetic_size)
+// 	}
+// }