[WIP/RFC] Fix issues if BeamspotConstraint is false

[andresailer]

Addresses some issues from #22 and a few memory issues (access, memory leaks)

Todo:

• [x] @nachogargar is currently testing

comments are already welcome

• [ ] Please tell me there is a better way to store the on-the-fly created vertex in the existing collection and replacing the nullptr Vertex inside the first entry, instead of doing const_cast (https://github.com/lcfiplus/LCFIPlus/compare/master...andresailer:primVtx?expand=1#diff-d5939a2753951ddbb81d7c60554d505cR195) .

BEGINRELEASENOTES

• Fix crash when BeamspotContraint is false
• Fix memory leak in VertexFinderSuehara

ENDRELEASENOTES

[jstrube]

Pinging @suehara, @tomohikosan to provide expert review.

[nachogargar]

I have tested the patch from @andresailer and it worked for me. I checked both BeamspotConstraint = 1("true") and 0("false")

[protopopescu]

Tested and works fine for me too.