made z input in vel_functions have default of 0.  Also added big TODO list for tasks on hold
Merge branch 'master' into vel
Merge pull request #27 from s-pearce/vel

Vel
Ported some functions to C (pygsw)
Merge pull request #28 from lukecampbell/improved-pygsw

Ported some functions to C (pygsw)
Fixes broken test
Merge pull request #29 from lukecampbell/test-fix

Fixes broken test
Fixes syntax errors
Merge pull request #30 from ooici/bug-fixes

Fixes syntax errors
Improves performance of CO2 function

Also adds groundwork for performance testing
Merge pull request #31 from lukecampbell/perf-work

Improves performance of CO2 function
Starts updating cdt functions

Updates ctd_sbe16plus_tempwat to utilize numexpr
Merge pull request #32 from blazetopher/start_ctd_updates

Starts updating cdt functions
Finishes CO2 funciton improvements
Merge pull request #33 from lukecampbell/perf-work

Finishes CO2 funciton improvements
Patches pygsw ver
Improvements to qc_functions

Starts improving qc_functions
* Adds rolling_window to utils module - efficient generation of windows along an array
* Adds 'strict_validation' flags to all dataqc_* functions
* Improved internal looping of dataqc_spiketest
Merge pull request #34 from blazetopher/qc_func_improvements

Improvements to qc_functions
Refactors some tests and begins tests for qc profiling
Merge pull request #35 from lukecampbell/qc-performance

Refactors some tests and begins tests for qc profiling