better detection of docs theme
- if installing directly from a wheel, fail if it has an invalid name or is unsupported
- when walking links, skip invalid wheel filenames, don't crash
unsuppress --log-file
add 'distribute' to default skip list for installed dists
add warning to --egg option, see https://github.com/pypa/pip/issues/1320
Merge pull request #1321 from qwcode/skip_distribute

add 'distribute' to default skip list for installed dists
Merge pull request #1316 from qwcode/log_file

unsuppress the help for --log-file
Merge pull request #1315 from qwcode/check_wheel_support

don't crash when crawling invalid wheels;  if installing directly, fail if invalid or unsupported
Ignore leading and trailing whitespace
Add a comment
Test the entry points parsing
Merge pull request #1311 from mwilliamson/py3-symlinks

Fix: "pip install ." fails on Python 3.3 (with symlinks in local directory)
Merge pull request #1307 from dstufft/fix-entrypoints-parsing

Ignore leading and trailing whitespace
Fix shutil.copytree for py3 when a symlink points to a directory
Prevent circular symbolic links
Add test with circular symbolic links