Update emake.py to version 3.7.11 and add method check_dirty for handling dirty files and auto building if needed.

3.7.10: xlink optimization

3.7.8: new environment variables: EMAKE_FLAG, EMAKE_CFLAG, EMAKE_CXXFLAG to provide a new way to add compiler arguments

update doc

update emake.py

new xlink option for llvm-ld

bloat version number to 3.7.7

Merge pull request #22 from wanzzhehe/fix_printmode

Merge pull request #21 from wanzzhehe/fix_update

fix print mode not work

fix update source default type from str to bytes

update doc

update README

fixed: python3 download/update issues

Update emake version to 3.7.5 and date to Sep.11 2024. Modify the HTTP URLs to use HTTPS. Add a new test function (test11) to update the files.