修改了错别字
Merge pull request #109 from xiaoqiangkx/master

修改了错别字
Merge from internal version
Add compile dependancy of targets which generated header files,
Allow prebuilt cc_library has only static/dynamic library
Add option to control action of duplicated source compiling
Dot allow cc_plugin be linked in and prebuilt, only cc_library allow export_incs