New example and startupadigator removed

[stefphd]

• Brachistochrone example with initial position (0,0) and final position (2,2). Solved using numerical differentiation and trapezoidal discretization. Results were successfully compared to those found using other optimal-control software (namely GPOPSII).
• startupadigator (and related lines) removed from 'transcribeOCP_eachPhase.m': indeed, adigator should be considered already installed. The persisent variable 'adigatorGen' removed b/c no longer necessary.