handle comments and empty lines directly in the parser's main loop

note that comment handling is currently a bit too simplistic as stuff
like

FOO
'-- hello' /

won't work. as far as I can see, this is not different from the state
before this patch, though.
don't enter the parsing main loop if the leftover-from-last time keyword does not have any records
Parser::parseState(): remove the 'verbose' debugging facility

This one could only be enable by modifying the source code. If such
debugging output is needed, it should be directly added via std::cout
and removed it before proposing the PR...
Well(Injection|Production)Properties: adapt it to the naming and style conventions of the rest of the module

this patch only changes the conventions which are internal to the
code, i.e., users of these classes do not need to be adapted...
Merge pull request #339 from andlaus/low_level_improvments

Low level improvments