Adds an output argument to EN_addnode and EN_addlink that returns the index of the newly added object.
Also refactors the validity check on object ID names.
The newly added `gettitle` and `settitle` functions were moved from the Reporting Functions section to the Project (formerly System) Functions section of epanet2.c and epanet.c.
1. Added a standard header to each code module and removed obsolete comments.
2. Re-named several of the sub-structs in the project struct and re-arranged some of their contents.
3. Re-named _defaultModel to _defaultProject.
4. Removed the need to call EN_createproject and EN_deleteproject when working with the default project.
5. Made X & Y coords. part of Snode properties instead of a separate struct.
6. Moved the non-API functions in epanet.c into a new module named project.c.
7. Re-factored the quality module so that it uses the same nodal adjacency lists as the hydraulics solver.
8. Re-factored the sparse matrix module (smatrix.c) to be more memory efficient.
9. Restricted line lengths to < 90 columns.
10. Grouped the placement of functions in EPANET2.H and EPANET.C by category.
- Deleting controls with node/link deletion made conditional.
- New EN_addrule function added along with a test file.
- Rule structures re-named & rules.c heavily modified.
- Issue with exceeding limit on number of temporary file names fixed.
- VB declaration and DEF files updated.
