Re-factored default_beta_ladder outside PTSampler object, and added optional arguments for specifying Tmax instead of ntemps.
Added flatchain property to ptsampler.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	emcee/ptsampler.py
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Add bcast collective operation to the MPIPool class
Merge branch 'master' of https://github.com/dfm/emcee

Conflicts:
	emcee/ptsampler.py
Fixed bug related to recent upstream merge in ptsampler.py
Merge remote-tracking branch 'upstream/master'
Changed to p(z) ~ 1/z choice of scaling parameter in stretch move.
emcee/interruptible_pool.py: new SIGINT-friendly pool wrapper.

Python's multiprocessing.Pool interacts badly with KeyboardInterrupts,
which is annoying if your parallelized emcee run encounters problems.
This new module wraps the builtin Pool with a shim class that avoids
these problems. It's based heavily on the solution proposed by
John Reese:

  http://noswap.com/blog/python-multiprocessing-keyboardinterrupt
emcee/ensemble.py: default to using InterruptiblePool rather than the stock Pool
setup.py: add a hashbang line

If the executable bit is set, there should be one!
PEP8
more PEP8 and documentation
updating changelog and adding @pkgw to contributor list
Merge pull request #114 from pkgw/pr-setup-hashbang

Add a hashbang line to setup.py
Merge pull request #111 from farr/master

PTSampler Temp Ladder Changes Merged with 2.0.0
reverting @farr's proposal change for now :smile:
typo