1、修改StringToDateConverter，使日期格式根据传入的长度确定转换格式。相应修改spring-mvc.xml的配置信息
2、添加Excel导入支持。
Merge remote-tracking branch 'origin/master'

Conflicts:
	ruclabmis-web/src/main/java/edu/ruc/labmgr/web/controller/converter/StringToDateConverter.java
	ruclabmis-web/src/main/webapp/WEB-INF/spring-mvc.xml
Merge remote-tracking branch 'origin/master'