介绍一个字符串转换的函数组SCMS_CONV

函数组SCMS_CONV下包含了若干字符串转换的函数，包括二进制，文本，string，xstring之间的相互转换，

SCMS_BINARY_TO_FTEXT
SCMS_BINARY_TO_STRING
SCMS_BINARY_TO_TEXT
SCMS_BINARY_TO_XSTRING
SCMS_FTEXT_TO_BINARY
SCMS_FTEXT_TO_STRING
SCMS_FTEXT_TO_TEXT
SCMS_FTEXT_TO_XSTRING
SCMS_STRING_TO_FTEXT
SCMS_STRING_TO_XSTRING
SCMS_TEXT_TO_BINARY
SCMS_TEXT_TO_FTEXT
SCMS_TEXT_TO_XSTRING
SCMS_XSTRING_TO_BINARY-->通过XML转换将内表中内容下载成.xlsx格式的excel文件