Backtrader

- Fixes 51 - a trade may reopen a position but close a trade if overlapping
(different tradeid) trades are active
- Address Pull Request 52 by adding Py 2/3 MAXINT compatible "constant" which
is imported into TradeAnalyzer and used instead of sys.maxint
- Fixes 50 by correcting open/popen typo in StopLimit order

- Fixes 46 by adding a default of total.total = 0 to indicate that no trades
were executed and therefore no statistics
- Fixes 46 by adding a default of total.total = 0 to indicate that no trades
were executed and therefore no statistics
- CalendarDays filter implementation and added sample
- Removed gitter from README

- Filters moved to submodule filters
- Full docstring update for CommInfoBase
- Small improvements to internal AutoDict/AutoOrdereDict
- Implementation of Trade history log (40)
- Added __bool__, __nonzero__ to Position for position testing
- Orders support miscellaneous information from end-users (42)
- Trades get unique identifier and datetime for opening/closing time (42, 43)
- Corrected typo in iteritems (38)

- Addition of keys, values, items to py2/3 compatibility layer
- Add getdatanames to strategy
- Strategy.buy/sell/close take data or name as key for operation
- Close 37 pannotated typo in "atclose" order type in broker
- Close 35 adding getpositionbyname, getpositionsbyname, getpositions and the
associated properties without "get"

- 33 correction of typo added during correction of 33
- Added getdatabyname and string_types check in buy/sell/close to retrieve
datas in Strategy

- Fixes 33 by properly adjusting the cash for existing open futures (added
long comment to explain the logic)
- TimeReturn analyzer added. Can calculate returns for all timeframes
- SharpeRatio updated to use TimeReturn including automatic adjustment of
the (annual) riskfreerate for timeframes days, weeks, months. It can still
use the legacy AnnualReturn analyzer
- CommInfoBase added as root of all commission schemes to make commission
schemes more flexible by not tying margin to commission type deduction
- Added 4 CommInfoBase derived classes with standard commission schemes
- Extended broker.setcommission call with parameters to work with the new
CommInfoBase
- Implemented the legacy CommissionInfo as a subclass of CommInfoBase, fully
retaining the existing behavior
- Some in-code documentation updates