fix issue in internal_file_entry when assigning an empty string that's borrowed

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9072 a83610d8-ad2a-0410-a6ab-fc0612d85776
compact chained_buffer::buffer_t

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9073 a83610d8-ad2a-0410-a6ab-fc0612d85776
improve svn usage in run_regression_tests.py

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9078 a83610d8-ad2a-0410-a6ab-fc0612d85776
exit on first error when building unit tests

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9081 a83610d8-ad2a-0410-a6ab-fc0612d85776
do less cleaning, save CPU and time when running tests

git-svn-id: https://svn.code.sf.net/p/libtorrent/code/trunk@9082 a83610d8-ad2a-0410-a6ab-fc0612d85776