Tradingstrategy

- Closes 230 by closing the pool on completion rather than waiting for
garbage collection
- Default to show unleveraged value and allow retrieval of leveraged
value
- Update btfd sample to updated leveraged value
- Improve order value reporting with leverage
- Correct dataseries TimeFrame name presentation in writers
- Doc updates

- Added pair-trading sample from remroc: PR 223, 224, 225
- Some documentation updates
- Leverage support
- Closes 227 numfigs type=int in arg parsing
- Correct no-plotting of datas
- Correct pandasdata integer addressing issue
- Correct time comparison when running with runonce=True
- Update SessionFiller to more stringent standards in modern versions

- Add time comparison for single line operations
- Correct plotting error calculations with volume and improve data on data
- Remove cosmetic comma

- PR 221 Correct onda candleFormat parameter
- Allow data on data plotting and no data plotting
- Remove double labeling on indicators
- Analyzer LogReturnsRolling
- Observer LogReturns
- Improved order management of input for validity
- Set default end date for online downloads in Yahoo if not set
- Gold vs SP500 Sample

- PR 195 make runstrats iterable to allow callbacks
- Fixes 189 by adding callback during optimization
- Fixes 205 to avoid errors during unnamed argument usage in strategy
- Regression correction for no short-cashing

- PR 212 added Vortex indicator
- Closed 215 writer opens file in binary mode
- Closed 210 missing comma in status definitions lists in feed
- PR 203 python3 compatiblity for ib (long)
- Added shortcash parameter to broker to control cash increase/decrease