Fix build script.
Fix build script.

- Change shell path and file mode
- go get md2min instead of blackfriday

astaxie/build-web-application-with-golang,astaxie/build-web-application-with-golang,songqii/build-web-application-with-golang,admpub/build-web-application-with-golang,faxriddin/build-web-application-with-golang,admpub/build-web-application-with-golang,faxriddin/build-web-application-with-golang,admpub/build-web-application-with-golang,admpub/build-web-application-with-golang,songqii/build-web-application-with-golang,WangKaimin/build-web-application-with-golang,astaxie/build-web-application-with-golang,WangKaimin/build-web-application-with-golang