1. In frame of the fix for #27282 issue, we have obtained several prolonged curves, which have common point(s). Fix for this issue joins these curves if it is possible.
2. ElCLib::InPeriod(...) method has been improved. Now it has become more faster (in general cases) and more reliable (in frame of FLT_OVERFLOW and DIVISION_BY_ZERO cases processing).
Creation of test case for issue #27302
Test case tests\bugs\modalg_6\bug27282_2 has been adjusted in accordance with its new behavior.