added fields entrypoint and imagebase to pe_file_t
- Fixed possible fd leak on pe_load() when an error happens
Merge pull request #4 from felipensp/fix_fd_leak

- Fixed possible fd leak on pe_load() when an error happens
readme update
build dir removal in make clean
Add 2 missing subsystems, inspired by 76ea354.
Thanks to Dmitry Mostovenko.
Merge branch 'mmap' of github.com:merces/libpe into mmap