Merge pull request #1451 from qwcode/deprecations

consistent deprecation messages
Explicitly test for setuptools and not pkg_resources
The future is pip 1.5
Merge pull request #1453 from dstufft/test-for-setuptools-not-pkg-resources

Explicitly test for setuptools and not pkg_resources
Merge pull request #1454 from dstufft/fix-documentation

The future is pip 1.5
If --allow-unverified is used assume it also means --allow-external
Merge pull request #1457 from dstufft/dont-require-external-and-unverified

If --allow-unverified is used assume it also means --allow-external
use `Logger.deprecated` for deprecation warnings
Merge pull request #1450 from qwcode/pip_first_install

`get-pip`-first instructions, due to vendoring pkg_resources
replace the ez_setup instructions with simple pip commands
show what commands are deprecated in `pip -h`
merge from 1.5.X
initial breakup of req.py
fix req pkg imports
remove req.py
fix references to req methods/classes after refactor