con. enh., psi estimation
FIX: attach asources as bads, not meg channels
FIX: fix test
ENH: Added temporal decimation to Morlet analysis

To help minimize memory usage when processing large datasets, added decim
parameter to `single_trial_power` and `cwt`.

This allows me to analyze some datasets where the final result of
`single_trial_power` would not have fit in memory otherwise.  Having `cwt`
perform the decimation before returning the result also sidesteps the issue of
multiple jobs (using joblib) returning large arrays to the parent process that
crashed my Python interpreter.

Includes:
* docstring fix for `single_trial_power`
* bugfix where `single_trial_power` was not calling `cwt` with correct
  arguments when njobs was 1.
* Updated some code to use the decim argument to `cwt` rather than decimating
  after the function returns the data.
* Updated two examples to showcase the decim argument.
Merge pull request #553 from bburan-galenea/bburan/tfr-decim

ENH: Added temporal decimation to Morlet analysis
Merge pull request #555 from dengemann/ica_epochs

FIX: attach sources as bads, not meg channels
ENH: Add non-replacement to events
WIP: time_shift() method for Epochs class.

However, the unit test fails right now. Comments and reviews welcome!
No more bugs in shift_time_scale() method in Epochs class

The method name in the Evoked class has also been modified.
Corrected dashes in the docstring
Preloading of data not required. Ancient relic that must be discarded
Added example for time-shift and added time-shift in events.py
Dropped support for time-shift in Epochs class in favor of time-shift at the events level
Changelog modified conforming to the usual practice of appending newer changes to the bottom
Shorter name for time-shift in Evoked class
Small mistake in whats_new.rst rectified
MISC : cleanup time shift
typo
Merge pull request #556 from Eric89GXL/events-combine

WIP ENH: Add non-replacement to events
cleanup