0028385: Improve drawing isolines (DBRep_IsoBuilder algorithm)
1. When computing the iso-lines for the face (*DBRep_IsoBuilder*) prepare the Hatching algorithm with the following elements:
a. Trimmed p-curves of edges. The trimming parameters are computed by intersection with p-curves of the neighboring edges. The trimming will be performed only if the intersection point is covered by the tolerance of common vertex.
b. 2D segments connecting the p-curves of the neighboring edges. These segments will close the 2D gaps, which are closed in 3D by the tolerance of vertices shared between edges. This will allow trimming correctly the iso-lines passing through such gaps.
2. Implementation of the additional Init() method for WireExplorer algorithm taking UV bounds of the face to avoid their repeated computation when work working with a face having multiple wires.
3. Test cases for the issue.

- [DB] tests/bugs/modalg_7/bug28385_10