Include max_investment argument in the runSimulation method of tti.indicators package

[vsaveris]

Currently, in the runSimulation method of the tti.package, all the buy trading signals are processed, without any limitation on the investment.

This can bring some unrealistic scenarios, in case of a high number of consecutive buy signals. In that case the investment can become very high.

For this reason a new input argument should be introduced (max_investment). In case where max_investment already reached, new buy signals are being ignored, till some balance becomes available with a sell trading signal.

Simulation code, and returned simulation data should be updated accordingly. ignored_buy_signals entry should be included in the returned statistics.

Target release 0.1.b3

Tasks:

• [x] Update runSimulation method in the _technical_indicator.py module (tti.indicators package), as described above
• [x] Include additional tests for the runSimulation method in the test_indicators_common.py

[vsaveris]

Description of the new argument:

max_investment(float, default=None): Maximum investment for all the opened positions (short and long). If the sum of all the opened positions reached the maximum investment, then it is not allowed to open a new position. A new position can be opened when some balance becomes available from a position close. If None, then there is no upper limit for the opened positions.

[vsaveris]

Development is done, ready for test cases development.