Various enhancements for isoductility response spectra

Improved functionality for generation of constant ductility response spectra

Various bugs fixed, examples added and other enhancements made.

阿里亚斯的计算强度和significant duration are corrected. Minor updates at the help section of the main routine OpenSeismoMatlab.m

Baseline correction enhanced
与未校正的地面运动的累积梯形数值整合有关的错误是固定的。
Additional output related to earthquake input energy and predominant PSa and period is given by the algorithm

Screenshot updated

Resampling capability added for increasing or decreasing the size of the time step of the input acceleration time history.

Baseline correction added

Code improved