Merge pull request #83 from andlaus/fix_more_conversion_factors

fix more (hopefully all) conversion factors
fix JSON of the PVTO keyword

the magic word is "num_tables" and not "size". with the latter it only
parses the first record of the keyword. Stupid me!
add dimensions to PVTG
add class for simple tables

This is intended for keywords like SWOF which currently is a big
vector of doubles but one needs to use the data in a column oriented
way.

This class is intended to be used like this:

Opm::DeckKeywordConstPtr swofKeyword = newParserDeck->getKeyword("SWOF");
Opm::SimpleTable swofTable(swofKeyword,
                           /*columns=*/std::vector<std::string>{"SW", "KRW", "KROW", "PCOW"},
                           /*recordIdx=*/table_num);
const std::vector<double>& sw = swofTable.getColumn(0);
// ...

what might be useful is to move the column names into the JSON
description of the keywords, but I could not find a way to go back to
the parser from the deck/keyword. maybe this is not even desireable as
decks might also be created by other means...

Also, a multi-record variant of the class is available. That one is
intended for keywords like PVTO where the first few items of each
record form a table (in the case of PVTO: Rs, pressure, Bo, and
viscosity for staturated oil) and the next entries constitute another
table (in the case of PVTO: pressure, Bo and viscosity for
undersaturated oil with the same RS factor as the first entry).

The second kind of tables can be constructed using the item-based
variant of SimpleTable.
add support for full-fledged tables