resolve symlinks in local files

the tar libraries choke when checking valid
filenames because they don't resolve symlinks
Merge branch 'hotfix/1.0.2'
Merge pull request #245 from ptone/find-links-symlinks

resolve symlinks in local files
Merge branch 'release/1.1'
Merge branch 'release/1.2'
Merge branch 'release/1.2.1'
Merge branch '1.3.X'
Merge branch '1.3.X'
fix proxy support
deal with travis installing ssl backport by default
Decode downloaded contents.

Also add a test (the exact url depends on pulling a change to pip-test-package).
Change test_requirements:test_remote_reqs to use hltbra's gist

g2p's pull request for issue #760 requires changes on pip-test-package.
The gist was created to remove this dependency.
Move python3/python2 details from ``download.get_file_content`` to backwardcompat module
Tweak variable name at backwardcompat.get_http_message_param (python 2 version)
update changelog
update usage patterns for 'pip wheel'
check for proper distribute when using wheels
spurious file
wheel requirement checks with tests
Merge pull request #885 from qwcode/distribute_check

wheel requirements checks with tests